(CNN) -- Former Yale University lab technician Raymond Clark III has been sentenced to 44 years in prison for the grisly killing of a graduate student in 2009, according to court officials.

Judge Roland Fasano sentenced Clark, 26, on Friday in New Haven, Connecticut, Superior Court as part of a plea agreement, said Rhonda Stearley-Hebert, a spokeswoman for the Connecticut Judicial Branch. Fasano pleaded guilty in March to the murder and attempted sexual assault of pharmacology student Annie Le.

Le, 24, was strangled to death. She had a broken jaw and collarbone, the prosecution said. Clark's DNA was "all over" the crime scene, including in her underwear, the state charged.

Le was pursuing a doctorate degree at Yale when she went missing on September 8, 2009. Her body was discovered inside a wall of a campus lab building after an extensive search by the FBI and police.

Clark admitted the facts as the prosecution presented them but pleaded guilty under a legal precedent that allows him to do so while still officially protesting his innocence

He pleaded guilty under the so-called Alford doctrine, which allows a defendant to assert that he is innocent but plead guilty when he "intelligently concludes that his interests require a guilty plea and the record strongly evidences guilt."

Clark had pleaded not guilty in January 2010.

Le had planned to marry Columbia graduate student Jonathan Widawsky on the day her body was found.

Clark was not a Yale student but had worked as a lab technician at the university since 2004, after graduating from high school. He lived with his girlfriend, who also was a Yale lab technician, according to police.

A Yale faculty member described Clark's job as maintaining colonies for animals used in research.

CNN's Leigh Remizowski, Brian Vitagliano and Jesse Solomon contributed to this report.