A group of students who spent their undergraduate years at GW started Saturday night celebrating a birthday, but the night of drinking spiraled into accounts of a brutal murder.

GW graduate student Rahul Gupta, who had just turned 24, told officers that he killed a friend he had known since high school, Georgetown law student Mark Waugh, because he thought his girlfriend and Waugh were involved romantically behind his back.

“My girl was cheating with my buddy. I walked in on them cheating and I killed my buddy,” Gupta told officers the night of the stabbing in Silver Spring, according to police documents.

Gupta was charged with second-degree murder, or killing without premeditation, according to the documents. The District Court for Montgomery County has scheduled a preliminary hearing for Gupta for Nov. 8.

Gupta allegedly pulled a knife from a butcher block and stabbed Waugh seven or eight times in the neck, chest and back, puncturing one of Waugh’s lungs. Waugh, 23, tried to defend himself against the attack, the Washington Post reported a prosecutor saying during a hearing this week.

Gupta later told an officer that he had “fucked up,” adding that Waugh also tried to stab him.

“Guy’s a real dick. He tried to kill me and my family,” Gupta said to the officer.

Waugh was a James Madison University alumnus and a first-year student at the Georgetown University Law Center. He and Gupta had gone to Langley High School in northeast Virginia.

Armin Aflaki, a GW graduate public health student, was one year below Waugh and Gupta at the suburban high school of about 2,000 students. Aflaki took a sports medicine class with Waugh as a freshman in high school, where he remembers talking about their shared affinity for the Redskins.

“He was a very sociable, likable kind of guy,” said Afklaki, who also earned his bachelor’s degree from GW. “It’s a big loss. It’s really a shame.”

As an undergraduate, Gupta won a prestigious research award from the Office of the Vice President for Research. Chemistry professor Susan Gillmor, who served as his mentor for the project, said Gupta was a “terrific student” in her lab, but declined to speak further.

A former classmate told The Hatchet that Gupta was smart, hard-working and “always talked enthusiastically about what he was building” for engineering projects. He was also athletic and spent a lot of time at the gym, the classmate said.

The classmate, who spoke on the condition of anonymity to protect his career, said he last talked to Gupta a couple weeks ago, and Gupta mentioned he was interested in pursuing a Ph.D.

Gupta started GW’s graduate program in biomedical engineering this fall. He also worked in a bioengineering lab for nanomedicine and tissue engineering.

Gupta had spent Saturday evening with his girlfriend and another friend – who all had graduated from GW in 2012 – for Gupta’s birthday.

At some point in the night, Gupta, his girlfriend and Waugh went to the couple’s apartment in Silver Spring. The three took shots of alcohol, then Gupta’s girlfriend said she blacked out, documents show.

She said she woke up to Gupta yelling for her to call 911 and saw Gupta kneeling over Waugh, who was unresponsive and bleeding heavily.

Officers heard movement and screams inside when they arrived at about 3:30 a.m. When they opened the unlocked door, Gupta’s girlfriend, covered in blood, ran toward them and said, “I don’t know what happened. Can you tell me?”

The officers saw blood on the walls of the kitchen and living room, then found Gupta on the floor, also covered in blood.

In court, Gupta’s attorney questioned the arrest record that showed Gupta telling officers that he “walked in on” Waugh and his girlfriend cheating. The Post reported that his attorney pointed out that the apartment was a studio.

Gupta told officers his girlfriend’s screams had awoken him, and when he turned towards her, he saw Waugh sitting on the floor against a bed and “bleeding out.” He said he knew Waugh was suffering from a stab wound, even though “that information had not been disclosed to him by investigators,” according to documents.

Marisa Kashino, a spokeswoman for Georgetown, said the school currently did not have plans for a memorial service for Waugh. A release from the university called Waugh a “bright young man, full of potential.”

“At this time, the investigation into Mark’s death is ongoing and we have no additional information to share,” the release read.

– Sarah Ferris contributed to this report