BOSTON -- Investigators continue to sift through clues in the slaying of a Boston graduate student who was found dead in a vacant lot in New York City last weekend.

Imette St. Guillen, 24, who was working toward a master's degree in criminal justice in New York, was found nude, strangled and suffocated Saturday after a friend left her alone at a bar early in the morning.

NewsCenter 5's Shiba Russell reported that police are now analyzing security videos from the Manhattan bar where St. Guillen was last seen.

The video shows St. Guillen arguing with her friend around 3 a.m. Saturday outside the Pioneer bar in the Bowery because St. Guillen wanted to stay and her friend, West Roxbury native Claire Higgins, wanted to go home. Higgins waves goodbye and then leaves in a cab while St. Guillen heads back into the bar alone. About 30 minutes later, Higgins called St. Guillen on St. Guillen's cell phone and St. Guillen said she had moved to another bar in the same neighborhood.

Later that evening, about 8:30 p.m., police found St. Guillen's body in a vacant lot in Brooklyn's East New York section, her ankles bound with shoe laces, her head wrapped in packing tape. She had been sexually assaulted. Police released pictures of a flower print bedspread in which St. Guillen's corpse was wrapped. They said the bedspread is the kind sometimes used in inexpensive motels and they're searching area motels now for more clues.

Detectives are also trying to identify the man who called police on 911 from a Brooklyn diner, tipping them off about the body in the vacant lot.

St. Guillen's mother, Maureen, and her sister appeared on MSNBC Tuesday night, pleading with anyone who has information to come forward.

"We're just hoping that someone out there says something, if they saw anything, or if they know anything, just the smallest detail, she just ... you know, nobody deserves this," Alejandra St. Guillen said.

St. Guillen, who was from Boston, was scheduled to graduate this semester from John Jay College of Criminal Justice in Manhattan. She attended George Washington University as an undergraduate and graduated magna cum laude.

"Really, what we want to do is just concentrate on the positive things and the life of my daughter and not focus on all the negative aspects," she said. "She was a beautiful girl, I mean beautiful inside also. She was kind, she was loving and she wouldn't hurt anyone," Maureen St. Guillen said.

The family earlier said it plans to establish a scholarship in her name at Boston Latin high school, where she was a 1999 graduate.