Middle-school student Nicole Lovell was stabbed to death the day she went missing from her home in Blacksburg, Virginia, according to preliminary findings released by investigators.

Authorities also announced a new charge in the case, but they left key questions unanswered as they spoke to reporters Tuesday: How did two Virginia Tech students end up crossing paths with the 13-year-old, and why would one of them allegedly abduct and kill her?

“My responsibility to Nicole Lovell and this community is to maintain the integrity of this case for court and to seek justice inside of a courtroom,” Montgomery County Commonwealth’s Attorney Mary Pettitt said. “I will not jeopardize the many hours of work these officers have done for Nicole. Therefore, I will not be releasing any additional factual information outside of the courtroom.”

Nicole Lovell went missing early on January 27, spurring an extensive search that led to the discovery of her body three days later in a wooded area in North Carolina.

Pettitt said that stabbing was “a very preliminary determination of the cause of death” in the case. She announced a new charge against one of the suspects.

Virginia Tech student Natalie M. Keepers now faces a charge of being an accessory to murder before the fact, the prosecutor said. The 19-year-old had already been charged with concealing a body and being an accessory to murder after the fact.

Her classmate, 18-year-old freshman David E. Eisenhauer, faces abduction and murder charges.

Attorneys for the two did not respond to requests for comment.

Investigators have been tight-lipped about the evidence they have that allegedly ties the two college students to the killing. In an arrest warrant for Keepers obtained by CNN, authorities gave a date range for when they believe her alleged connection to the case began: January 4-January 27.

Police arrested Eisenhauer late Friday. He was already facing charges the next morning, before Nicole’s body was found.

Eisenhauer did not lead authorities to the body, according to Blacksburg’s police chief, nor did he confess to murder. Still, authorities managed to piece things together after sorting through social media, exploring 300-plus tips and searching for other information pertinent to the case.

“These are the kind of crimes,” police Chief Anthony Wilson said last weekend, “that rip communities apart.”

Victim loved pandas, ‘American Idol,’ mom says

Outside the ground-floor apartment where Nicole lived, there is evidence of more carefree times: a bicycle, a yellow Tonka truck, a few plastic chairs.

A small bouquet of pink and white flowers rests on a table, in the low 40-something temperatures, a reminder of a family’s inconceivable loss.

Tammy Weeks, Nicole’s mother, held a stuffed panda bear in her hand as she spoke to reporters about her daughter.

The girl’s favorite color was blue. She loved pandas and dancing, and dreamed of making it big on “American Idol” someday.

Time after time, Weeks said, the girl she called “Coley” beat the odds.

First, there was a rare tumor in her liver that was diagnosed as a baby. Then there was a lymphoma fight that led relatives to think they’d “almost lost her a second time.” And third, there was a bout with acute respiratory syndrome and antibiotic-resistant staphylococcus that led doctors to give her a mere 1% chance to make it.

Somehow, Nicole survived all that, her mother said.

“Nicole was a very lovable person,” Weeks said. “Nicole touched many people throughout her short life.”

At that point, a trembling, sobbing Weeks abruptly left the press podium and the room. Josh Blankenship, a pastor at Auburn Baptist Church, finished reading from her prepared statement.

“Our hearts still ache in sadness and secret tears still flow,” Blankenship said. “What it meant to lose you, no one will ever know.”

Suspects could face life in prison

Eisenhauer faces a sentence of 20 years to life if convicted for first-degree murder, the same sentence Keepers could face if she’s convicted of accessory before the fact.

The university the suspects attended dominates Blacksburg. Lantern Ridge, the apartment complex where Nicole lived, sits amid the maze of mostly student housing roughly a half mile from Main Street, which goes downtown to the Virginia Tech campus.

Despite their age difference, Eisenhauer — a celebrated cross-country runner in Columbia, Maryland, prior to coming to Virginia Tech — at least knew Nicole before her disappearance, according to police.

“We have determined that Eisenhauer and Nicole were acquainted prior to her disappearance,” Blacksburg police Lt. Mike Albert told reporters last weekend. “Eisenhauer used this relationship to his advantage to abduct and then kill her.”