Updated

A key witness overheard a graduate student from Boston arguing with a suspect in her brutal murder — a bouncer at a SoHo bar — before she disappeared and later turned up dead in Brooklyn, a law enforcement official said on Tuesday.

Imette St. Guillen, 24, was raped, strangled and suffocated by someone who stuffed a sock in her mouth and wrapped her head with packaging tape before dumping her body on a desolate road in Brooklyn on Feb. 25.

St. Guillen, a student at John Jay College of Criminal Justice in Manhattan, was last seen alive at The Falls bar. Initially, witnesses said she had quietly walked out the door alone when the bar closed at 4 a.m., police said.

But the bar's owner and his lawyer came forward late last week and revealed that he had ordered the bouncer, a 41-year-old parolee identified by news outlets as Darryl Littlejohn, to toss her out when she complained that she was not being allowed to finish a drink, the official said. The owner said he later overheard "some sort of arguing and a commotion" as the bouncer took the woman outside, the official said.

The official, who spoke to The Associated Press on condition of anonymity because no one had been charged in the killing, said investigators have cell phone records possibly linking the bouncer to the East New York spot where St. Guillen was found. The records show his phone was used in the same vicinity about two hours before police — responding to an anonymous 911 from a public phone — discovered her naked and bound body.

On Sunday, police began questioning the bouncer, who has convictions for armed robbery and other crimes. He was being held at the 75th Precinct on a parole violation while investigators did forensic testing on possible evidence collected during searching of The Falls and his home.

Parole officials said the man was conditionally released in 2004 after serving time for a 1995 bank robbery conviction. He allegedly violated the conditions of his parole by failing to observe a 9 p.m. curfew, the officials said.

The bouncer's aunt told reporters outside his home in Queens that she could not believe he was responsible for the crime.

"To me, this would be out of character for him," Addie Harris said. "Even though he had a past record, it had nothing, no type of violence or anything in it that I know toward women."

A $42,000 reward has been offered for information leading to an arrest and conviction.