text: [Themes: edutainment]
  
  You are a detective living in London, Ontario. Crime has peaked in recent years and you have often been called to aid in police investigations. You take pride in your work and have created a good reputation with the London Police. You must be careful not to lose it - otherwise you will no longer be called to help with investigations. You have also studied toxicology prior to becoming a detective - which is an asset in your ability to understand the science portion of crime.
  
  One evening, you receive a phone call from Constable Oliver Peterson, an experienced policeman and old friend.
  
  "Oliver! How have you been?" you exclaim.
  
  "I've been good, but unfortunately the reason for my call is anything but that. A body was found about an hour ago on the shores of the Thames River. As of now, there has been no identification, but we believe this case may be connected to the string of killings surrounding the Thames. Will you look at the case for us?" he asks.
  
  What do you do?
  
  > Agree to help investigate the murder
  "I'm on board," you tell Constable Peterson.
  
  "I'm glad to have your help on this one," he sighs. "Drop by the station tomorrow morning and I'll get you up to speed."
  
  The next morning, you drive down to the station and are greeted by Chief Morrison. He escorts you into his office and tells you to have a seat.
  
  "I'm afraid this is an extremely sensitive case and your detective help as well as your background in forensic toxicology will be extremely beneficial." he remarks. He goes on to tell you that a body was found at the shore of the Thames River last night. This morning, a match was found in the Missing Persons Database. The victim was Lauren Ross, a 22 year old nursing student at the University of Western Ontario. After a preliminary examination, signs of struggle were evident. She had several bruises and cuts scattered over her body, but the most significant damage done was the dismemberment of her ring finger on her left hand. Cause of death was unknown, but the local lab should have results within the next hour.
  
  You ponder the information the Chief has just told you. In the past year, the bodies of two women in their 20's have been found near the Thames River, six months apart. They were both missing the same finger, the left ring finger. The police force had been hesitant to label the murders as connected in order to avoid public fear, but you begin to wonder if you can avoid it any longer. This third victim makes it impossible to deny what citizens had been hoping wasn't true: London is being terrorized by a serial killer.
  
  "That seems consistent with the murders of Jacqueline Brooks and Sydney Thompson," you note.
  
  "I'm afraid so. We'll hold a press conference later today." he murmurs, glancing out the window. "But before that, you need to take some time to look over the case. Come visit me in my office around noon and let me know what your thoughts are at that time and we can prepare our statement. I'll make some calls, but it is likely the press conference will be held around 1."
  
  Part of you has interest in visiting the lab and learning the results, but another part of you wants to visit the crime scene. After some consideration, you tell the Chief what you plan to do.
  
  > visit the crime scene
  Upon arriving at the crime scene, you spot Constable Peterson.
  
  "Have you already visited Chief Morrison?" he asks.
  
  "Actually, I was just at the station," you respond.
  
  You survey the markers spread throughout the area. This particular section of the shore is a few meters away from a hiking trail, where you notice some civilians are standing and observing the crime scene.
  
  > talk to civilians
  You excuse yourself and make your way towards the civilians.
  
  There is an older couple standing together in tears. A few feet away a young blonde girl stands solemnly. Towards the back of the trail, a middle aged man in overalls is looking down at his phone.
  
  As you near them, you must decide who to talk to first.
  
  > talk to the couple
  You decide to talk to the older couple.
  
  "Hi, I'm with the London Police Service. Do you mind if I ask you a few questions?" you ask.
  
  The woman wipes away a tear and gives you a distasteful look, then turns to her husband and says, "It's like we're being questioned! How rude."
  
  The man looks up at you and sighs. "She's right, you know. The least you could have done is say that you're sorry for our loss. Have you ever thought about what it's like for the families of murder victims?"
  
  You apologize and leave the couple alone.
  
  > talk to the girl
  You decide to talk to the girl.
  
  "Hi, I'm a detective with the London Police Service. Do you mind if I ask you a few questions?" you ask.
  
  "Not at all." the girl responds.
  
  "Tell me a little about yourself and any connections you may have with the victim." you say.
  
  "My name is Madison Howard and Lauren was my roommate. We are -", she paused "- were both in nursing together. I miss her more than ever. She didn't deserve this - no one does. I can't imagine what kind of person you'd have to be to commit murder. I just can't get my mind off of finding out who did it. Lauren deserves justice."
  
  "I'm sorry for your loss. You are certainly right, which is why I am determined to catch her killer. Can you think of anyone she might've been meeting last night? Or anywhere she went?" you ask. She looked down at her shoes for a few seconds.
  
  "She was going on a date. She recently signed up for a dating website after she broke up with her boyfriend. He might be useful to question - he was always jealous of other guys. He always was a little crazy..." she trailed off.
  
  "Thanks Madison, I really appreciate your help." you exchange contact information and bid her farewell.
  
  > talk to the man
  You decide to talk to the man.
  
  "Hi, I'm a detective with the London Police Service. Do you mind if I ask you a few questions?" you ask.
  
  "I'm busy. Sorry" the man says, not looking up from his phone.
  
  > keep talking to the man
  "This is a murder investigation. You know I can charge you with obstruction of justice, right?" you say.
  
  The man still doesn't look up from his phone. "You won't do shit." he spits.
  
  You sense that you should move on and leave the man alone.
  
  > go back to Constable Peterson
  You make your way back to Constable Peterson.
  
  "Ready to be briefed now?" he asks and you nod.
  
  > Get briefed
  "The body was found here around 10 pm last night. As you know, her left ring finger was missing and has not been recovered. This is the third victim to be found in similar conditions, so we are labeling this as part of the serial killer's M.O. We've just found some navy blue fibers and they're on the way to the lab for testing. Other than that, some footprints were found but I don't have high hopes of obtaining anything of value from them. So many people come through this area because of the trails, the best we could do is use the mold of the footprint as supportive evidence, but only after we find our serial killer." Constable Peterson says.
  
  "Was the body dumped here or did it wash up from the river?" you ask.
  
  "It seems that he body washed up during the high tides. Some joggers spotted it and called the police right away." he responds.
  
  You thank Officer Peterson for his time and leave the crime scene.
  
  > go back to the police station
  Once you arrive at the station, you see Chief Morrison walking out of his office.
  
  "Detective! Have you visited the lab yet?" he asks.
  
  > Yes
  You tell him about your findings.
  
  "Arsenic... this is thoroughly consistent with the two other murders. At this point there is little to no chance this isn't a serial killer at work. This press conference isn't going to be pretty." he says.
  
  You agree, and help Chief Morrison prepare the official police statement. It states that Lauren Ross is officially the third victim in a string of murders and warns civilians in the target range of young females to be alert at all times. The press conference goes relatively well, but you feel the pressure on you increase drastically now that the case was declared part of a larger scheme.
  
  You feel that you need to take some time to look over the facts of the case and create a plan for what to do next, but you also would like to revisit the lab to run tests on the navy blue fibers that were found earlier that morning.
  
  What do you choose to do?
  
  > go home and look over the case
  You decide to go home and look over the case. You spend the evening flipping through the case files of the previous two victims, as well as the current case.
  
  The next morning, you visit the lab.
  
  > go to the lab
  You wake up feeling refreshed and ready for the day. You drive to the lab and greet Dr. Fischer. You ask if the fibers found yesterday have been tested yet and he tells you that his intern ran a mass spectrometry test and found atrazine.
  
  You are hesitant about this and suggest running the test again to confirm the results. Dr. Fischer reluctantly agrees, and you follow him into the lab. First, you place the fiber into a vacuum chamber inside the machine. Then, the fiber is shot with ions so that the atoms or molecules turn into ions (ionization). These ions shoot out from the vacuum chamber into an electric field, which causes them to accelerate. Ions from different atoms have different electric charges, so the ions spread out according to the amount of charge they have. The ions are then shot into a magnetic field , causing them to bend into an arc. Lighter particles (positively charged) bend more than heavier ones (negatively charged). They split into a spectrum, with each different ion bent a different amount according to its mass and its electrical charge. An electrical detector records a spectrum pattern showing the number of ions for each mass/charge. This is used to identify the atoms or molecules in the original sample.
  
  After running the mass spectrometer, you and Dr. Fischer notice confirm that there is a trace of atrazine (C8H14ClN5) on the fibers. Atrazine is a common herbicide used mainly on corn farms.
  
  Upon learning this, you theorize that Lauren may have been on a farm shortly before her death, or been in contact with someone who had. This was different than the other two cases, and you believe it is because the killer got too comfortable with his method and changed something - perhaps taking the victim to his own property before killing them.
  
  You recall that Lauren was also the only victim to fight back against her attacker. You believe that this could possibly result in her having her attackers DNA underneath her fingerprints.
  
  > mention this to Dr. Fischer
  You ask Dr. Fischer if any skin cells were found under Lauren's fingernails, and he tells you that a sample was collected during the autopsy. You propose to run some tests to analyze the sample in hopes of creating a useable STR profile.
  
  First, the sample would be amplified using an amplification kit for 31 cycles. The kit amplifies a maximum of 30 autosomal alleles per profile. Each STR amplification would contain 2.5 μl primer mix, 5 μl reaction mix, 0.5 μl DNA polymerase, and the DNA template. STR amplifications are carried out in groups of three, so alleles present in at least two of the three amplifications are then assigned to the DNA profile of the sample. The STR profile percentage is found by dividing the number of alleles detected by the number of known alleles for the sample.
  
  After running the amplification, you find the STR profile percentage to be 72%. You run this partial profile against the National DNA Data Bank (NDDB), but there are no matches.
  
  You thank Dr. Fischer and return to your car. You receive a call from Constable Peterson, who tells you that he questioned a bystander at the crime scene who was wearing overalls and seemed suspicious. He informs you that the suspect, Blake Russell, is currently at the police station being held for questioning. You tell him that you are on your way and to refrain from talking to him until you arrive.
  
  > go to the station
  You arrive at the station and are met by Chief Morrison.
  
  "He seems like a solid suspect. Farmer, who has a farm backing directly onto the Thames River. He recently went through a divorce, which would most likely be the trigger in this case." he tells you.
  
  From what you have heard, Mr. Russell seems like he could've done it, but you need to question him to see for yourself. You walk into the interrogation room and sit down.
  
  "Mr. Russell. I presume you understand why you are here?" you remark.
  
  "I haven't done anything wrong. Is minding my own business a crime now?" he mutters.
  
  "Well, you're here because you were uncooperative when questioned at the scene, and meet several of the criteria of our suspect. Tell me, where were you on the evening of November 27th?" you ask.
  
  "At home. I don't have an alibi, since I know that's your next question." he stares at the wall and sighs.
  
  "You work on a corn farm," you mention, "is that right?", and he nods. "So you are familiar with the herbicide atarzine?" you ask, and he nods again.
  
  "Did you killer Lauren Ross, or the other two victims?" you bluntly question.
  
  "No." he states, giving you a cold stare.
  
  You stand up and collect your things, ready to give Chief Morrison your final verdict.
  
  > Convict Blake Russell
  You decide to convict Blake Russell. Chief Morrison trusts your verdict and announces the police have caught the Thames River killer. The city of London is ecstatic and finally at peace. The trial goes smoothly, with the atrazine being used as the main piece of evidence. Circumstantial evidence was expertly delivered by the prosecution, and Mr. Russell was too poor to afford a lawyer for proper defense in his case. He was charged with all three murders and received a life sentence with no possibility of parole.
  
  You celebrate your victory with the police and look forward to working on cases together in the future.
  
  > 10 years later...
  One decade later, the Thames River case has been reopened, and Blake Russell has been declared innocent. You made a wrongful conviction and you have lost all your reputation and will not be hired to consult on a case again. As well, the London Police are now frowned upon by neighboring police forces. You did not have enough evidence, yet made a conviction regardless. Due to your actions, an innocent man spent ten years in prison.
  
  Maybe you should've thought about your decisions more thoroughly.