NEW HAVEN, Connecticut (CNN) -- The killing of Yale student Annie Le was not random and could have been committed by one of only a small number of people with access to the building where her body was found, authorities said.
Le's body was found hidden in a wall in the basement of a Yale medical research building Sunday, the day she was supposed to be married. The 24-year-old graduate student had been missing for a week. Bloody clothes were found hidden above tiles in a drop ceiling elsewhere in the building, investigators said.
Her killing was not a random act, New Haven Police spokesman Joe Avery said. He would not elaborate.
Yale University President Richard Levin told students Monday: "We know everyone that was in the basement. There were limited number of people in the basement and we passed that on to police. There is an abundance of evidence."
Yale professor Gary Rudnick, who interviewed Le when she applied for admission to the graduate program in pharmacology, told CNN that the building where Le's body was found had good security, and only certain people could enter, let alone access specific areas. He said the circumstances suggested there could be a "murderer among us."
Thomas Kaplan, editor in chief of the Yale Daily News, said Le's killing had left Yale students shocked and wary.
"Only Yalies had access to that basement, and that seems to point to someone in our community being involved in this," Kaplan said. "That's what is so frightening."
No suspects were in custody, but investigators were questioning several people in the case, police said.
Authorities have not described the clothes that were found, nor said to whom they might have belonged. Teams of investigators at a Connecticut State Police lab worked through the weekend processing and examining the bloodstained clothes.
Kaplan said a Yale police official told the paper that the clothes were not what Le was wearing when she entered the building.
Security cameras captured video of Le as she entered the four-story lab building at 10 Amistad Street, about 10 blocks from the main campus, on Sept. 8. After poring over hours of surveillance tapes, authorities said they had not found images of her leaving the building.
Le was to be married Sunday on New York's Long Island to Jonathan Widawsky, a graduate student at Columbia University.
Her friend Vanessa Flores said Le was overjoyed about getting married.
"She was just so excited about this wedding and everything from, you know, her flowers to her wedding dress and just certain details about it," Flores told HLN's "Nancy Grace. "We talked about this back in 2008. She was already thinking about the weather, whether June, July was going to be too hot, August, so September, would it be nice?"
Le was from Placerville, California, and seemed to have been well aware of the risks of crime in a university town. In February, she compared crime and safety at Yale with other Ivy League schools for a piece for B magazine, published by the medical school.
Among the tips she offered: Keep a minimum amount on your person. When she walked over to the research building on Tuesday, she left her purse, credit cards and cell phone in her office.
On Monday night at Yale, several hundred people turned out for a vigil for Le.
Her roommate, Natalie Powers, said Le "was as good a human being as you'd ever hope to meet."
"She was also really tenacious and had a sense of humor that was never far away, and she was tougher than you'd think by just looking at her," Powers said.
"That this horrible tragedy happened at all is incomprehensible, but that it happened to her, I think, is infinitely more so. It seems completely senseless."