BOSTON – Elsie “Yolanda” Hernandez was an 18-year-old cashier at a Roxbury department store who was looking forward to starting classes at Northeastern University when she was killed while walking home from work.

Her body was found in a garbage-strewn lot on Dec. 29, 1984, the day after she disappeared. Authorities said she had been raped, bludgeoned with a piece of concrete and strangled with an athletic sock.

For more than two decades, her killing remained unsolved. But in 2008, authorities said they matched a DNA profile taken from her body to DNA from Sultan Omar Chezulu, a Boston man who had been living in a halfway house near the crime scene.

Chezulu, who moved to Atlanta years later, was arrested there in 2008. His murder trial begins today in Suffolk Superior Court.

His attorney, Bernard Grossberg, said he vehemently denies any involvement in her death and offered to take a lie detector test.

“He didn’t rape her; he didn’t kill her,” Grossberg said. “He strongly maintains his innocence and wanted to take a polygraph, but a polygraph is not admissible in Massachusetts.”

Chezulu served time for rape and kidnapping in the 1970s and later served 14 years for attempted robbery and assault and battery with a dangerous weapon. After he was released from state prison in 2004, he was required to submit a DNA sample. It was that sample that eventually led investigators to him.

In 2007, a Boston homicide detective who was working on cold cases sent sperm recovered from Hernandez’s body to the FBI database known as the Combined DNA Index System, or CODIS, which contains DNA information from convicted felons and other unsolved cases. The sperm matched the DNA sample Chezulu had given three years earlier. Chezulu was arrested in 2008 in Atlanta, where he was working for a trucking company.

Chezulu, now 61, legally changed his name from Robert Scott years ago after converting to Islam, his attorney said.

Prosecutors said Hernandez was attacked shortly after 6 p.m. as she walked through a vacant lot from her job at Robell’s department store to her grandmother’s apartment, where she lived.

Her body was found the next day. Her pink work shirt and blue denim skirt were still on, but her underwear was found about 20 feet away. She had severe facial injuries, broken bones and abrasions.

Prosecutors would not discuss the case right before trial. After Chezulu’s arrest, Suffolk District Attorney Dan Conley called Hernandez’s killing “monstrous.”

“There can be no undoing what was done to her, but we can hold the man who did it to account for his actions,” Conley said the day of his arraignment.

Chezulu is charged with first-degree murder. Prosecutors said they could not charge him with sexual assault because the statute of limitations on that charge had expired before he was arrested.