In search of quick cash and drugs, two men set out for a College Park house where a University of Maryland student was known to sell marijuana, according to authorities and court records.

But the student fought back during the robbery attempt, according to law enforcement sources and court records, and was fatally shot. On Thursday, Prince George’s County police arrested the men they say are responsible for the death of the 22-year-old student, Justin Vance DeSha-Overcash.

Deandre Ricardo Williams, 23, of the District and Stephan Weaver, 22, of Bowie have been charged with first-degree murder in the Jan. 11 slaying. Williams is accused of shooting the victim, and Weaver allegedly drove Williams to the house.

“It’s bittersweet,” said Karen DeSha, the victim’s mother, who disputes that her son was a drug dealer. “My son lost his life, and all everyone wants to talk about is marijuana.”

According to police charging documents, a key break in the case came last Friday when a “longtime high school friend” of Weaver’s went to investigators with information about the killing. The informant was facing a heroin charge, according to law enforcement sources, but his detailed account of the killing convinced detectives that his information was sound.

According to the informant’s account in court records, the suspects had heard from a friend that there were usually a lot of money and drugs inside a house in the 8800 block of 38th Avenue. On Jan. 11, according to the account, Weaver drove Williams and himself a block from the house, where Williams handed him a gun and told him to wait in the car.

One law enforcement source said Weaver thought they were there to conduct surveillance. The source and others quoted in this article spoke on the condition of anonymity because they were not authorized to speak publicly and could be disciplined for discussing the case.

A short time later, according to the informant’s account, Williams returned to the car and told Weaver that he had shot DeSha-Overcash after he resisted during a robbery, and then they sped away. The informant told detectives that he had learned what happened from Weaver.

Neither suspect knew DeSha-Overcash, a Prince George’s police spokeswoman said.

After the gunman entered the house, law enforcement sources have said, witnesses overheard him repeatedly asking for the victim by name — apparently not knowing DeSha-Overcash was right in front of him.

The sources have said DeSha-Overcash smashed a glass jar full of marijuana on the gunman’s head in an attempt to get away, after which he was shot.

DeSha said that she was aware that police have known of suspects in her son’s killing for some time but that she kept mum to not jeopardize the investigation. She said she continues to dispute that her son, a senior working toward a double major in physics and astronomy, was a drug dealer, although she acknowledged that police recovered marijuana and scales from the house. Law enforcement sources have said they also recovered marijuana-laced lollipops.

DeSha said she thinks that the drugs belonged to others in the house and that charging documents provide the account they do because police had “to word things a certain way to be able to get warrants.”

“I don’t care if there was marijuana in that house — my son’s life was taken,” DeSha said.

Authorities said Williams and Weaver have acknowledged their involvement in the incident. A law enforcement source said the suspects’ vehicle was seen on College Park traffic-enforcement cameras the day of the killing.

Weaver is a 2006 graduate of DeMatha High School, where he played varsity baseball in his sophomore and junior years, according to a school spokesman. His Facebook page says he studied business economics at the University of West Virginia. A post to that page made via ­iPhone at 6:09 p.m. on the day of the killing says: “PG county is way to crazy for me.” The slaying was reported about 11:30 a.m.

A man who answered the phone at Weaver’s family’s home in Bowie declined to comment and said the family had been advised not to comment. No one returned a written message left at the door. Robert C. Bonsib, Weaver’s attorney, said in an e-mail that he was investigating the case and would “respond to the allegations in court at the appropriate time.”

Less is known about Williams. People who answered the doors at addresses associated with him in public records said they did not know him. Court records show he was convicted of a drug charge in Prince George’s in 2008.

Staff researcher Madonna A. Lebling contributed to this report.