NEW HAVEN, Conn., Sept. 14 (UPI) -- Investigators looking into the slaying of a Yale University graduate student said Monday they were focused on a suspect who failed a lie detector test.
Police sources said they believe the suspect knew Annie Le, 24, whose body was found Sunday -- the day she was to have been married -- behind a wall in a laboratory building near the Yale Medical School. They told ABC News the man had defensive wounds.
The medical examiner positively identified the body and ruled the cause of death to be homicide, but did not specify the manner of death.
New Haven Officer Joe Avery told reporters Le's death "doesn't appear to be a random act," The New York Times reported.
Video cameras showed her entering the building about 10 a.m. Tuesday, but none showed her leaving, the newspaper said.
Le was to have married a Columbia University graduate student Sunday in Long Island, N.Y.
The newspaper said bloody clothes were found in a drop ceiling in the building housing the lab, where Le was doing a research project. Her cell phone, wallet and keys were found in her nearby office at Yale Medical School.
More than 100 federal, state, city and university law enforcement officers had been searching for Le since Tuesday night, when her roommate reported her missing.
Yale University in New Haven, Connecticut 
A graduate student attending Yale University who went missing five days before her planned wedding was found dead on Sunday, police said.

Annie Le, an American doctoral student seeking a degree in medicine, went missing on September 8, five days before her planned wedding. Investigators reviewed footage from the security cameras of 10 Amistad, the building where Le last entered, and found no evidence that she had left. Police scouring the building found a body, later identified as Le's, hidden in a wall. Earlier, police had found bloody clothes in the ceiling, which they think belonged to the killer.

According to the medical examiner, Le had been strangled.

Le was set to marry Jonathan Widawsky, a graduate student studying physics at Columbia University.

Police believe that there was a motive, and that the slaying was not random. A lab technician, who was labeled a "person of interest" by police, had failed a polygraph and had defensive wounds on his chest, was detained and later released. However, no arrests have been made in connections with the homicide, according to a police spokesman.

In December 1998, Suzanne Jovin was found murdered on the Yale campus.