A bouncer with a long rap sheet has been charged with murder in the death of a graduate student from Boston who was savagely raped, strangled, and dumped last month in a desolate area of Brooklyn, two law enforcement officials said yesterday.

An announcement of a murder indictment against Darryl Littlejohn, 41, was expected today, said the officials, who spoke on condition of anonymity because the indictment was still sealed.

The developments mark a major breakthrough in a gruesome case that drew national attention ever since Imette St. Guillen’s body was found February 25 with a sock stuffed in her mouth and her head wrapped with packaging tape.

St. Guillen’s mother, Maureen St. Guillen, was seen leaving her home in Boston yesterday morning in a car filled with suitcases. She left with her daughter and son and spoke briefly with reporters, saying she wished “my baby was home” then started crying.

A call to Littlejohn’s attorney was not immediately returned. Prosecutors declined comment.

Littlejohn has maintained his innocence, with his lawyer contending he was being made to be a scapegoat because police couldn’t find the real killer. But authorities say they uncovered blood and other evidence linking the parolee to the slaying.

In a jail interview with WCBS-TV, Littlejohn denied killing St. Guillen and said police “have the wrong person.” He said he was asked to escort St. Guillen out of a bar where she was drinking just before closing; his attorney did not allow him to be questioned about what happened next.

Littlejohn said he had provided a DNA sample when asked. “I cooperated fully, even before I was placed under arrest,” he told WCBS for the interview, which was conducted on Tuesday and aired yesterday evening. Asked whether he killed St. Guillen, he said, “No, I did not.”

St. Guillen, 24, was last seen alive after a late night of drinking at the Falls bar, a SoHo nightspot where Littlejohn worked as a bouncer.

A manager at the bar has told police Littlejohn escorted her out after she stayed sipping a drink past the 4 a.m. closing time; he recalled hearing the pair arguing before they disappeared through a side door. Sometime during the next 17 hours, the student at John Jay College of Criminal Justice in Manhattan was killed.

Investigators soon set their sights on Littlejohn, a career criminal whose record includes robbery, drug, and gun convictions, and locked him up on a parole violation as they slowly built their case. Authorities say they collected evidence showing that Littlejohn’s cell phone was used in the area where the body was discovered. They also claim the suspect’s blood was found on the plastic ties used in the crime. The ties were used to bind the 24-year-old’s hands behind her back, the city’s police commissioner, Raymond Kelly, said last week.