NASHVILLE, Tenn. -- A man pleaded not guilty on Wednesday to the 1975 slaying of a Vanderbilt student.

Jerome Barrett is charged in the death of 19-year-old Vanderbilt student Sarah Des Prez. Des Prez was found dead in her apartment by her father and brother.

The state claims that DNA ties Barrett to Des Prez’s death.

Barrett was scheduled to appear in a Nashville courtroom, but he waived his right to appear. His attorney, Kerry Haymaker, entered the plea on his behalf.

There is not a lot of information in the case. The key piece of evidence, police said, is the DNA.

According to Channel 4 News' sources, DNA evidence has also linked Barrett to Marcia Trimble’s death, though he has not been officially charged. Trimble was found dead about a month after disappearing in 1975. She was last seen delivering Girl Scout cookies in her Green Hills neighborhood.

Barrett was arrested in Memphis on charges stemming from the Des Prez case. He was released from prison in 2002 after serving 26 years for the rape of a Belmont student. According to records, Barrett was on parole for a sex offense when he raped her.

Barrett remains uncharged in the Trimble case.

According to sources close to the case, Barrett is connected to six attempted rapes, rapes and slayings. Seven other rapes were also reported about the same time.

Former rape Detective Ralph Langston said there was never any investigation into the possibility of a serial rapist. He said police didn’t use the term at that time.

Langston said to read the articles that were written about the story at the time. He said six rapes were investigated by six different detectives.

“Most of those case files were kept by individual detectives except what was turned in to Central Records. ... We worked three shifts. ... All detectives worked every personal crime that could happen to a human being back then,” he said.