More than four years after Dr. Louis Chen was charged after the knife attack that killed his partner and toddler son, his defense team revealed in court documents that it intends to argue Chen’s use of over-the-counter cough syrup contributed to his psychosis. 
 
 It’s been more than four years since Dr. Louis Chen was charged with aggravated murder in connection with the deaths of his longtime partner and their toddler son, but the first hint of his likely defense — that cough syrup contributed to his psychosis — only recently emerged during a legal debate over an expert witness. 
 
 Suspected prescription-drug abuse and a looming child-custody battle are described in search warrants as possible motives for the deaths of Eric Cooper, 29, and 2½ -year-old Cooper Chen, whose bodies were found inside their 17th-floor apartment in Seattle’s First Hill neighborhood in August 2011. 
 
 While Chen’s defense team announced nearly three years ago that it intended to pursue an insanity or diminished capacity defense at trial, the basis for that defense remained a mystery. 
 
 That is, until the defense filed a motion in October suggesting Chen was suffering from cough-syrup induced psychosis as a result of a buildup of the drug dextromethorphan in his system. The motion further intimates that the drug metabolized slowly in Chen, who is Taiwanese, due to his genetic makeup. 
 
 The revelations were made as the defense sought to bar an expert witness — a former state forensic scientist who resigned under a cloud as the head of the State Patrol Crime Lab in Seattle — from testifying when Chen, now 43, is tried on two counts of aggravated first-degree murder in April. 
 
 King County Prosecuting Attorney Dan Satterberg decided early on he would not seek the death penalty against Chen, leaving life in prison without the possibility of release as the only possible punishment should Chen be found guilty of aggravated murder. 
 
 It wasn’t immediately clear if cough-syrup-induced psychosis had ever been used as the basis of a defense in a murder trial in the state. 
 
 “I’ve definitely heard of induced psychosis through taking various drugs,” but never a criminal case involving cough syrup, said University of Washington law professor Mary Fan. 
 
 She said cough syrup can produce the equivalent of a high, and like any drug that’s misused or abused it can lead to intoxication. 
 
 “It’s really going to come down to, is it voluntary or involuntary (intoxication)?” she said. “That’ll be a big issue.” 
 
 Recent move 
 
 Chen, an endocrinologist, had recently moved to Seattle with his family from North Carolina for a job at Virginia Mason. When he didn’t show up for his first day of work on Aug. 11, 2011, a hospital manager went to Chen’s apartment, court records say. 
 
 When Chen opened the door he was naked and covered in dried blood. Police found the bodies of Cooper, who had been stabbed more than 100 times, and the couple’s son Cooper Chen, whose neck had been repeatedly cut, the records say. 
 
 An officer asked Chen, “who did this?” and Chen responded, “I did,” according to records. 
 
 Search warrants filed in the case indicate Chen was in the midst of an acrimonious breakup with Cooper. 
 
 Inside Chen’s apartment, homicide detectives found a variety of medications, along with prescriptions and blood-soaked notes written by Chen, which they say provided evidence of a possible dual motive: that Chen feared Cooper would report his prescription-drug abuse and the abuse of his prescribing powers as a doctor, or use that information against Chen in a future child-custody dispute. 
 
 Police also reviewed Chen’s finances since Chen had promised to pay Cooper $130,000 in the event their relationship ended, the warrants say. 
 
 An analysis of Chen’s blood showed he had dextromethorphan, a cough suppressant in many over-the-counter cold and cough medicines, as well as the anti-anxiety drug Xanax, and an antihistamine in his system. 
 
 Chen spent 10 days at Harborview Medical Center, where he was treated in intensive care for an overdose of medications and self-inflicted stab wounds, according to a heavily redacted mental-health evaluation by psychiatrists at a state psychiatric hospital. He reported hallucinations and had to be restrained for a few days because he had assaulted nurses while delirious. 
 
 While the Western State Hospital doctors could not provide a psychiatric diagnosis, largely due to a lack of information, they determined Chen showed no signs of psychosis or symptoms of a major mental illness at the time of his evaluation in December 2011. 
 
 They also noted Chen was only given antipsychotic medication by staff at the King County Jail after persistent, repeated requests from Chen and his defense attorneys. 
 
 Defense differences 
 
 Though insanity and diminished capacity are both mental defenses, they are conceptually different. 
 
 Insanity requires the defense to prove a defendant, at the time a crime was committed, suffered from a mental disease or defect to such an extent he or she was unable to understand “the nature and quality of the act” committed, or was unable to tell right from wrong, according to state law. 
 
 With an insanity defense, even if a defendant admits he or she intended to commit the crime, the act was done under a delusion. 
 
 Voluntary intoxication does not constitute insanity under the law. 
 
 With diminished capacity, however, any incapacitating factor — including voluntary intoxication — can be considered when evaluating a defendant’s state of mind. Basically, one’s mental condition was so diminished that he or she could not form the intent required to commit the crime. 
 
 In Chen’s case, mental-health evaluations conducted by defense experts are not part of the public record, so at this point there are only hints as to what may be presented at trial to support an insanity or diminished-capacity defense. 
 
 The defense contends Chen was suffering from psychosis in the days before and after the killings. That psychosis was caused, in part, by his use of an over-the-counter cough syrup containing dextromethorphan, says a declaration filed by attorney Todd Maybrown in October. 
 
 “The defense will also present evidence that Dr. Chen has a genetic makeup which compromises his ability to metabolize this chemical,” he wrote. 
 
 The argument appears to allude to scientific research showing a wide variability in how quickly people metabolize certain drugs based on production of a key enzyme. It appears that people of Asian descent may have a 50-50 chance of being born with a functioning gene variant for the normal metabolism of drugs like dextromethorphan. But roughly 40 percent of Asians and Pacific Islanders have reduced function, indicating a slower metabolism, according to a 2002 article in The Pharmacogentic Journal. 
 
 Slow or poor metabolism can increase the chances of adverse drug interactions or lead to a toxic buildup in the body. 
 
 Debate over testifying 
 
 Chen’s cough-syrup defense only came to light amid a larger debate over whether former state toxicologist Barry Logan would be allowed to testify against Chen. 
 
 Logan resigned as director of the Patrol’s Forensic Laboratory Services Bureau in 2008 after a panel of King County judges found he bore much of the blame for the lab’s sloppy work, ethical lapses and “fraudulent and scientifically unacceptable” practices in analyzing breath tests used to prosecute drunken drivers. 
 
 That same year, Logan went to work for a private laboratory in Pennsylvania. 
 
 Logan has authored or co-authored at least three articles in scientific journals about dextromethorphan abuse and the drug’s psychological effects, including psychosis, hallucinations and mania. 
 
 At the highest levels, dextromethorphan — found in products like Robitussin and Coricidin Cough & Cold — can lead to a dissociative state, resulting in violent, unpredictable behavior, likely without the intent of the individual, according to Logan. 
 
 The question of whether to allow Logan to take the stand had little to do with his actual research, instead centering on the issue of fairness since Logan had consulted with the defense and then two years later was retained by the state. 
 
 In June 2013, Maybrown, the defense attorney, discussed Logan’s research in connection with Chen’s criminal case, according to court records and court arguments. Maybrown ultimately decided not to retain Logan as a defense expert due to concerns about Logan’s “professionalism and business practices,” the records say. 
 
 But two mental-health experts hired by the defense referenced Logan’s journal articles about dextromethorphan in opining that Chen was psychotic, and therefore incapable of premeditating or intending to kill the alleged victims, Senior Deputy Prosecutors Don Raz and Mary Barbosa wrote in their reply brief. 
 
 Raz had hired Logan after confirming Logan had not been retained by the defense — and included Logan’s name on the state’s preliminary witness list in September. That prompted Maybrown to file a motion seeking to disqualify Logan from testifying, arguing he had been privy to confidential information. 
 
 King County Superior Court Judge Bill Bowman ultimately ruled Logan will be allowed to testify as a rebuttal witness, but only if the defense’s mental-health experts take the stand before Logan does. 

 First Hill doc charged in deaths of son, partner; could face execution 
 
 
 
 
 
 
 
 
 
 Photo: JOSHUA TRUJILLO Image 1 of / 3 Caption Close Image 1 of 3 Seattle Police work a crime scene after two people, including a child under 5, were found dead in an apartment on Thursday, Aug. 11, 2011, at the M Street Apartments in Seattle's First Hill neighborhood. less Seattle Police work a crime scene after two people, including a child under 5, were found dead in an apartment on Thursday, Aug. 11, 2011, at the M Street Apartments in Seattle's First Hill neighborhood. Photo: JOSHUA TRUJILLO Image 2 of 3 Courtesy of KOMO/4 less Courtesy of KOMO/4 Image 3 of 3 Seattle Police spokesman Sgt. Sean Whitcomb speaks to reporters after two people, including a child under 5, were found dead in an apartment at the M Street Apartments in Seattle's First Hill neighborhood Thursday, Aug. 11, 2011. less Seattle Police spokesman Sgt. Sean Whitcomb speaks to reporters after two people, including a child under 5, were found dead in an apartment at the M Street Apartments in Seattle's First Hill neighborhood ... more Photo: JOSHUA TRUJILLO First Hill doc charged in deaths of son, partner; could face execution 1 / 3 Back to Gallery 
 
 A First Hill doctor found naked and bloodied Thursday morning after his partner and 2-year-old son were fatally stabbed has been charged in their deaths. 
 
 Filing aggravated murder charges Tuesday, King County prosecutors claim Dr. Louis C. Chen killed Eric Cooper and the couple’s 2-year-old son, Cooper Chen, in their First Hill apartment. 
 
 Chen, 39, could face a death sentence if convicted in the slayings. King County Prosecutor Dan Satterberg has not yet decided whether to seek execution in the case. 
 
 Chen, who recently accepted a position at Seattle’s Virginia Mason Medical Center, has been hospitalized since he was found seriously injured at the apartment the day Cooper and the boy were found dead. 
 
 The doctor is now charged with two counts of aggravated first-degree murder, a charge that carries a sentence of either life in prison without release or the death penalty. King County Prosecutor Dan Satterberg will in coming weeks decide whether to file a notice of intent to seek the death penalty. 
 
 In court documents, Seattle police claimed Chen told officers he killed his partner. Chen was discovered naked and covered in blood at their apartment Thursday morning. 
 
 At 9 a.m. the day the killings were discovered, a property manager at the M Street Apartments received a phone call from Chen's sister who said she had not heard from her brother in days, Seattle Detective J.D. Mudd told the court. 
 
 Responding to a request from Chen's sister, the property manager knocked on Chen's door and spoke with him briefly. The property manager told him his sister was hoping to hear from him, and Chen said he would call her. 
 
 By then, Chen had already missed a 7:50 a.m. orientation at Virginia Mason Medical Center, where he'd accepted a position weeks before. Concerned, a manager from the hospital attempted to reach Chen by phone and then went to his apartment building. 
 
 The property manager and Chen's colleague then went to Chen's apartment and knocked on the door. Standing outside, they heard a rustling sound, Mudd told the court, and then looked on as Chen opened the door. 
 
 "The defendant was wearing no clothes," the detective said in court documents. "He was covered in dried blood, his right eye was swollen shut, and he was holding a box in front of himself." 
 
 Standing in the threshold, one of the women could see Eric Cooper lying on the apartment floor. Chen's colleague asked about his son; the woman told police she thought Chen said "baby" but offered no other reply. 
 
 Chen's colleague called 911, and reported seeing a square knife similar to a cleaver. 
 
 Seattle officers arriving at the apartment at 10:20 a.m. found Chen slumped in the front door, then located Eric Cooper's body. Stabbed several times in the torso, Eric Cooper had already died. 
 
 Cooper Chen was found in the bathroom of the master bedroom. He too was already dead. 
 
 An autopsy performed by the King County Medical Examiner's Office later showed Eric Cooper suffered more than 100 stab wounds; he'd been stabbed in the face, neck, torso and hands. Cooper Chen's throat had been cut. 
 
 One of two officers arriving at the scene then asked Chen about the slayings. 
 
 "Who did this?" the officer asked. 
 
 "What?" Chen responded. 
 
 "Stabbed you and him," the officer continued. 
 
 "I did," Chen said, according to Mudd's report. 
 
 Reviewing access logs for the apartment, investigators learned Chen and Cooper's key fobs – pass cards that allowed access to the lock-out building – hadn't been used since Aug. 8, three days before the deaths were discovered. None of those close to Chen reported seeing him after that date. 
 
 While investigators stop short of saying so, the impression given is that Chen had not left the apartment since that Monday, and that the killings may have occurred any time between then and when the bodies were discovered. 
 
 Five knives possibly used in the slayings were recovered from the apartment. All had blood stains on them. 
 
 Investigators do not note whether Chen made any other statements to police, or give any indication what might have motivated the attack. 
 
 Authorities at Virginia Mason Medical Center told KOMO/4 Chen was recently hired at the hospital and had been expected to start work Monday. They grew concerned he didn't show up for an orientation session the day the killings were discovered. 
 
 Chen and the slain man had lived together in Chicago and Chapel Hill, N.C., where Chen studied at Duke University, according to Associated Press reports. 
 
 According to a Seattle Times report, friends said Chen fathered the boy through a surrogate. Cooper Chen was then adopted by Eric Cooper. 
 
 Arguing successfully that Chen should be held without bail, Senior Deputy Prosecutor Don Raz described the doctor as a man with few ties to Washington and the money to flee. 
 
 "He faces either life imprisonment or the death penalty, has significant ties to Taiwan, and has access to financial means sufficient to arrange his flight," Raz told the court. "The defendant poses a significant risk of danger to the community based upon the serious penalties he faces combined with his exhibited willingness to use extreme violence." 
 
 Chen is expected to be booked into King County Jail after he is released from Harborview Medical Center. 
 
 With the death penalty still under consideration, attorneys for Chen will likely begin preparing mitigating materials in an effort to dissuade Satterberg from seeking a death sentence. The only penalties for aggravated first-degree murder -- the crime charged in the case -- are life in prison without the possibility of parole and death. 
 
 State law sets a 30-day deadline for prosecutors to file notice that a death sentence will be sought. In practice, that deadline is usually extended as defense attorneys evaluate the evidence in the case and any mental health issues that could sway the prosecutor. 
 
 Chen is scheduled to be arraigned Aug. 29 at the King County Courthouse. He is being held without bail. 
 
 Check the Seattle 911 crime blog for more Seattle crime news. Visit seattlepi.com's home page for more Seattle news. 
 
 Levi Pulkkinen can be reached at 206-448-8348 or levipulkkinen@seattlepi.com. Follow Levi on Twitter at twitter.com/levipulk. 
 
 
 
 Read more: http://www.seattlepi.com/local/article/Police-First-Hill-doctor-admitted-to-killing-2015853.php#ixzz1VD0Fh7CD
– A doctor accused of murdering his partner and their 2-year-old son in 2011 will go on trial in April next year—and he may blame cough syrup for the grisly killings. Louis Chen's defense team in October filed papers signaling that they will argue that the 43-year-old was suffering from psychosis caused by a buildup of the drug dextromethorphan in his system, reports the Seattle Times. The defense declaration suggests Chen's Taiwanese genetic makeup made it harder for him to metabolize dextromethorphan, found in many over-the-counter cough medications. Police have suggested Chen killed partner Eric Cooper because of an impending breakup and custody battle in which Chen's alleged prescription drug abuse may have been exposed, the Times reports. When Chen didn't show up for his first day at work in a Seattle hospital in the summer of 2011, police found him covered in blood at his apartment, along with the bodies of Cooper and their son, Cooper Chen, the Seattle Post-Intelligencer reported at the time. Cooper had been stabbed more than 100 times and the toddler's throat had been cut. Chen, who fathered the boy with a surrogate mother, spent more than a week in the hospital being treated for self-inflicted stab wounds. University of Washington law professor Mary Fan tells the Times that she has "definitely heard of induced psychosis through taking various drugs," but not in any cases involving cough syrup, and she predicts the case will hinge on whether Chen's "intoxication" was voluntary or involuntary. Chen faces life without parole.