A 13-year-old girl allegedly abducted and killed by a Virginia Tech student was stabbed to death, according to preliminary results, Montgomery County Commonwealth’s Attorney Mary Pettitt said at a news conference today. 
 
 A formal report of the cause of death has not yet been completed, Pettitt said. 
 
 Nicole Lovell, 13, of Blacksburg, Virginia -- the city where Virginia Tech is located -- went missing Jan. 27, the Blacksburg Police Department said. Her body was found on Saturday in Surry County, North Carolina, which is near the Virginia border, police said. 
 
 Investigators are working to reconstruct the timeline of both suspects, Chief Anthony Wilson of the Blacksburg Police Department said at a news conference this afternoon. 
 
 Virginia Tech student David Eisenhauer, 18, was charged Saturday with first-degree murder and one felony count of abduction, police said. 
 
 Virginia Tech student Natalie Keepers, 19, was charged today with being an accessory before the fact to first-degree murder, officials said. That charge carries a term of from 20 years to life in prison. She's also charged with concealing a body and being an accessory after the fact, which carry a maximum of 10 years and 12 months in jail respectively. 
 
 The police said investigators looking into Nicole's disappearance were led to Eisenhauer on Friday night. Eisenhauer was first charged on Saturday with one felony count of abduction, police said. Then after Nicole's body was found Saturday afternoon, he was also charged with murder, police said. 
 
 Eisenhauer and Nicole "were acquainted prior to her disappearance," police said this weekend. "Eisenhauer used this relationship to his advantage to abduct the 13-year-old and then kill her. Keepers helped Eisenhauer dispose of Nicole's body." 
 
 Eisenhauer's attorney, Chris Tuck, and Keepers' attorney, Kristopher Olin, could not be immediately reached by ABC News today for comment. 
 
 Eisenhauer, who is from Columbia, Maryland, ran cross country at Virginia Tech, and in 2015, while still in high school, he was named the Howard County, Maryland, indoor track Athlete of the Year, according to the Baltimore Sun. 
 
 Eisenhauer was a senior in high school in March 2015 when he was featured as a "Student Athlete of the Week" on ABC affiliate WMAR-TV in Baltimore. 
 
 "I just have this internal thing saying I want to be the best. There's no reason why I cannot be as good as other people are," Eisenhauer told WMAR-TV at the time. "I will personally not stop until I reach my peak performance which could be anywhere." 
 
 Eisenhauer told WMAR he wanted to run track in college and wanted "to get as many years out of it as I can. ... and I want to run for a school that has a good distance program or one that I feel that I will fit in with and excel." 
 
 Editor's note: A previous version of this story stated that Natalie Keepers was charged with first-degree murder. She was charged with being an accessory before the fact to first-degree murder. 
 
 Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here. 

 — Authorities say Nicole Lovell, a 13-year-old Virginia girl believed to have been abducted and killed by an 18-year-old Virginia Tech student from Maryland, was stabbed to death on Jan. 27 — the day her family discovered her missing from her Blacksburg home. 
 
 Mary Pettitt, the commonwealth's attorney for Montgomery County, where Blacksburg is located, revealed the preliminary results from an autopsy at a news conference Tuesday afternoon. Police also announced that charges were upgraded against a second Virginia Tech student from Maryland who they believe helped dump the girl's body off a highway in North Carolina. 
 
 Natalie Keepers, 19, of Laurel, is now charged with being an accessory before the fact to first-degree murder. The charge carries a maximum penalty of life in prison. She was earlier charged with improper disposal of a body and being an accessory after the fact in the commission of a felony. 
 
 David E. Eisenhauer, an 18-year-old from Columbia and a graduate of Wilde Lake High School, has been charged with first-degree murder and abduction in Nicole's death. 
 
 Authorities have offered no indication of why the girl was killed or how the two teens met her. Nicole's family has said she apparently pushed a dresser in front of her bedroom door and climbed out a window on the night she disappeared. 
 
 But a neighbor said the seventh-grader told friends she would sneak out to meet her "boyfriend," David, an 18-year-old she met online through the Kik messaging app. 
 
 Stacy Snider, whose 8-year-old twins played with Nicole, said that before she vanished, Nicole showed her girls Eisenhauer's picture along with a thread of texts they had shared, and said she would be sneaking out that night to meet him. 
 
 "She was talking about this boyfriend she had that was 18 and went to college, and his name was David. And showed some text messages off of a Kik and pictures. And that's what the girls told the police officers when they asked," she said. 
 
 Snider said she learned all this from her girls only after Nicole vanished. 
 
 "I would have told her mother," she said. "But we didn't know nothing about it until she came up missing, unfortunately." 
 
 Blacksburg police said they have evidence that Eisenhauer knew the girl before she disappeared last Wednesday, but provided no more details. 
 
 "Eisenhauer used this relationship to his advantage to abduct the 13-year-old and then kill her," a police statement said. 
 
 Kik Interactive, based in Ontario, Canada, was "active in helping the FBI carry out their investigation," spokesman Rod McLeod said. 
 
 Both Eisenhauer and Keepers were engineering students at Virginia Tech. Their attorneys have not returned calls seeking comment. Both students are being held without bond in Virginia. 
 
 Eisenhauer was the Howard County indoor track athlete of the year last year and a two-time Class 3A state runner-up in cross country. He was a member of the Hokies track team. He has been placed on interim suspension from the team, said Pete Moris, a university athletics spokesman. 
 
 Keepers participated in theater while at Hammond High School. The relationship between the two students from Howard County remains unknown. 
 
 Keepers is scheduled for arraignment on the latest charge Wednesday afternoon in Virginia. 
 
 Preliminary hearings for both teens are scheduled for March 28 in juvenile court. Virginia law requires cases to begin in juvenile court if the victim is a child, Pettitt said. After preliminary hearings, the cases will go before a grand jury and be tried in Virginia's Circuit Court, she said. 
 
 Nicole lived with her mother, Tammy Weeks, a few miles from the Virginia Tech campus. On Sundays, they rode the bus to Auburn Baptist Church in nearby Riner, Va. 
 
 The congregation and staff released a statement after Nicole's death. 
 
 "She was well liked by the other riders, her fellow Sunday School class students and the adult leaders," they said in the statement. "Our hearts are saddened by her sudden passing. We continue to pray for and minister to her family." 
 
 Members of the church are delivering meals to Weeks and helping with funeral arrangements. A visitation is scheduled for Wednesday evening in Blacksburg. Nicole's funeral is scheduled for the following afternoon. 
 
 Weeks spoke to reporters at the news conference Tuesday afternoon. Holding a worn stuffed panda bear belonging to Nicole, she spoke of how her daughter had bounced back from numerous health challenges as a small child, including a liver transplant when she was an infant and non-Hodgkin's lymphoma at 4 years old. 
 
 Nicole "tried to live a normal life," until the cancer came at age 4, she said. "We almost lost her." 
 
 She said doctors predicted Nicole had a 1 percent chance of surviving. 
 
 But she "beat the odds," her mother said. 
 
 Weeks read from a statement as Anthony Wilson, the police chief in Blacksburg, stood beside her and placed his hand on her shoulder. 
 
 "Music… dancing … [she] dreamed of being on 'American Idol' someday," said Weeks, the pitch of her voice rising against her tears. "Nicole was a very lovable person. Nicole touched many people throughout her short life." 
 
 There was more to read, but she stopped, unable to continue. 
 
 Shaking, she hurried from the room. 
 
 The Associated Press contributed to this article. 
 
 tim.prudente@baltsun.com
– A second Virginia Tech student is now facing life in prison in connection with the abduction and murder of a 13-year-old girl last weekend, ABC News reports. David Eisenhauer, 18, and Natalie Keepers, 19, were arrested on Saturday—the day Nicole Lovell's body was found in North Carolina and three days after she first disappeared from her bedroom in Blacksburg, Virginia. Eisenhauer was immediately charged with murder, while Keepers was charged with improper disposal of a body and being an accessory to murder after the fact, according to the Richmond Times-Dispatch. On Tuesday, authorities upgraded the charges against Keepers to include accessory to murder before the fact, which carries a punishment of 20 years to life. Authorities released charging documents and held a press conference Tuesday, but still little is known about the murder, the Baltimore Sun reports. Preliminary indications are that Lovell was stabbed to death on the same day she disappeared, but results from an official autopsy won't be available for weeks. Police say Eisenhauer used an unspecified relationship with Lovell to abduct her. Her mother, Tammy Weeks, says the two met online. No motive has been given for the crime, and authorities say Eisenhauer believes the truth will set him free. Weeks also spoke at Tuesday's press conference, remembering the daughter who "touched many people throughout her short life." Weeks says Lovell survived a liver transplant, lymphoma, and more. She loved pandas, Mountain Dew, and Dr. Pepper and wanted to be on American Idol.