The former George Washington graduate student convicted of killing Georgetown University Law Center student Mark Waugh was sentenced to life in prison on Wednesday.

A Montgomery County jury convicted Rahul Gupta, 25, of the first-degree murder of his 23-year-old roommate in March.

In October 2013, police found Waugh’s body, Gupta and Gupta’s then-girlfriend in the apartment the students shared in Silver Spring, Md. They discovered that Waugh had been stabbed multiple times.

According to The Washington Post, Gupta confessed to the murder immediately after police arrived at the Silver Spring apartment.

“My girl was cheating with my buddy. I walked in on them cheating and I killed my buddy,” Gupta told police at the apartment.

Waugh was a Georgetown law student at the time, while Gupta was pursuing a master’s degree in biomedical engineering at GWU. The two knew each other since attending Langley High School in Mclean, Va., together.

Throughout the trial, neither the prosecution nor the defense offered a motive for the killing. Gupta’s defense rested on an argument that his then-girlfriend, Taylor Gould, murdered Waugh, though Gould testified she did not remember the incident because she was intoxicated.

Gupta addressed the court at the sentencing hearing, apologizing for the incident, but not explicitly confessing to the murder.

“I’ll forever remember my time with Mark as a time of happy, simple intimacy,” Gupta said. “Words cannot describe how terribly sorry I am about what happened.”