Four days after the sudden death of sophomore Laura Treanor, the causes of her passing remain largely a mystery to her friends and family. Even as the details of that night emerge, few help explain why the 19-year-old never woke up Friday morning.

• Laura Treanor, 1989-2009
• Friends remember Treanor at memorial service, Catholic Mass
• Cause of student’s death remains a mystery
• Treanor was a positive and outgoing person
• Laura Treanor: Pondering the Pope
• Clayton McCleskey: A return to a spiritual path
• Brittany Levine: Remembering Laura: A life filled with charm, grace and good humor
• Staff Editorial: In Memory of Laura

Roommates discovered Treanor’s body in her bed at 8:30 a.m. on Friday morning and immediately called 911. Her nose and pillowcase were bloody, and she hadn’t changed her clothes from the night before. EMS and police units eventually arrived on 23rd Street, and a representative of the Medical Examiner’s office pronounced her dead at 10 a.m.

The Metropolitan Police Department announced soon after that there were no signs of trauma to the body, and a preliminary autopsy Friday night revealed that there had been no significant damage to Treanor’s organs, her mother said. A toxicology report and final cause of death are not expected for at least a month. Until then, those close to Treanor can only relive her final moments and wonder what went wrong.

At 6:30 p.m. Thursday, Treanor met a friend for dinner at Au Bon Pain. About two hours later, a roommate saw her painting her nails on their Ivory Tower couch. At 9 p.m. Treanor spoke to her father on the phone and said she was going out with some friends, her mother said. She then wrote on a friend’s Facebook wall and left Ivory Tower at about 11:30 p.m., roommates said.

Sophomore Max Mahoney, one of the last people to see Treanor alive, said she and a group went out to a bar, which several friends and bar patrons confirm was Adams Mill in Adams Morgan. She was seen entering at about 11:45 p.m. and several people who saw Treanor later in the evening said she did not appear intoxicated. Mahoney said he last saw Treanor “after midnight” in Ivory Tower and that there was no indication that she was sick.

Though Treanor had a habit of waking up her roommates after returning from a night out, the two roommates asleep Thursday never stirred and do not know what time Treanor arrived.

Ann-Marie Treanor says she still has no idea what killed her daughter, but wonders whether Laura’s prior medical conditions may have played a role.

She said in an interview Friday night that her daughter had recently complained of painful headaches and chronic bruising, and had been treated for Lyme disease in the fall – though Laura was not taking prescription medication at the time of her death, she said. She had also been diagnosed with hand, foot and mouth disease – a condition that affects the skin – in October and had seen a local hematologist. Roommates said the week before her death, Treanor showed them her palms, which had become largely black and blue.

On Friday afternoon, the University released a statement saying that it appeared Treanor died of “natural causes,” which University spokeswoman Tracy Schario said effectively rules out homicide pending a complete examination. The Natural Death Squad of MPD, not part of the violent crimes branch, initially responded to the scene and MPD spokesman Sgt. Kenny Bryson said Friday morning that it was not likely a suicide or homicide.

A police report filed on Friday offered sparse new details, except that police took a pair of Treanor’s earrings and two bracelets into custody – likely because she was wearing them when she was found.

University President Steven Knapp said in an interview Friday that the school is in communication with the family and does not know a cause of death.

“It just tells you once again how important it is for us to keep an eye out for each other and stick together as a community,” Knapp said. “Tragic things will always happen but we try to do everything we can to prevent them and to understand what people in the community are experiencing.”

A native of Yorktown Heights, N.Y., Treanor was born in 1989 and lived in a quad in the 23rd Street residence hall. The third-floor room was cordoned off on Friday, and Ann-Marie Treanor arrived Saturday morning to remove her daughter’s possessions.

Treanor, who was a sophomore with junior standing, was The Hatchet’s contributing life editor and a member of the Phi Sigma Sigma sorority.

A campuswide memorial is scheduled for Monday, Jan. 26 at 7:30 p.m. in the Smith Center. A memorial mass is scheduled in the Newman Catholic Center, where Treanor was a lector last year, for Tuesday evening at 5 p.m.

Nathan Grossman, Alex Byers, Sarah Scire and Emily Cahn contributed to this report.