NEW HAVEN, Conn. — The slaying of the missing Yale bride-to-be whose body was found on what was to have been her wedding day “wasn’t a random act,” police here said Monday as an autopsy concluded that she was the victim of a homicide.

Authorities also officially identified the remains as those of Annie Le, 24, the Yale doctoral student in pharmacology who had been missing since last Tuesday and whose body was discovered Sunday hidden inside a wall in a basement lab building where she worked in the medical school complex.

The medical examiner in Connecticut is withholding Le’s cause of death “for investigative purposes.”

Meanwhile, the New Haven Register reported that detectives were focusing on a lab technician who works in the building where the body was found.

The newspaper reported that the technician had failed a polygraph test and had scratches on his chest, as if he were in some type of a struggle.

Nearly all of the basement animal research floor where Le’s remains were found can be accessed only by students, faculty, staff and lab technicians who have been given specific permission to be there, student researchers said.

In an earlier statement e-mailed to the Ivy League school Monday, Yale Police Chief James A. Perrotti tried to tamp down rumors circulating on the shaken campus.

“There are no suspects in custody,” Perrotti said. “We ask for your patience as we thoroughly investigate this crime.”

Authorities would not answer questions about a suspect, but say they are sure that there are “no students involved” in Le’s killing, Perrotti said.

New Haven police spokesman Joe Avery said Monday that because the death did not appear to have been committed at random, there was no need for alarm on campus.

‘It wasn’t a random act,” Avery said. “It doesn’t appear to be a random act.”

Sari Levy, 18, a freshman at Yale from Great Neck, N.Y., said, “Everything is a little bit shaken up. It’s more like emotionally distressing than actually fearing for your own safety.”

Le, who is from Placerville, Calif., east of Sacramento, was to marry Jonathan Widawsky, also 24, a Columbia University graduate student from Huntington, N.Y., on Sunday. The nuptials were canceled Friday, after she was reported missing on Tuesday.

Widawsky is not a suspect and is working with investigators, police said.

Yale officials say every entrance and exit to the building on the school’s medical school complex is captured on video by a series of 70 cameras.

The basement where Le was found in a part of a wall used for utility cables and plumbing is highly secure, university officials said, and only students, faculty and staff with a need to be in the basement are able to go there.

At Le’s off-campus home about a mile and a half away, three plainclothes Yale police officers spent about 10 or 15 minutes in the residence Monday afternoon, then emerged with a camera. They would not answer reporters’ questions.

• Matthew Chayes