A Dupont Circle shoe store worker taking law school prep classes pushed away a shotgun and refused demands to hand over his property when he was fatally shot outside his apartment in March, D.C. police said in court documents describing the arrest of a suspect.

Akinwole Olu Williams, 31, was wearing a suit and carrying a white bag when he was confronted by at least three men about 11:40 p.m. March 14 at the front door of his building, in the 1000 block of 44th Street NE.

A witness told detectives that Williams pushed away the brown sawed-off shotgun held by one of the men, then walked toward the gunman, according to the court documents. Seconds later, the witness heard a gunshot and saw Williams clutch his chest and collapse to the ground.

D.C. police announced Wednesday night that they arrested Deandre Shaheed, 18, of Northeast Washington and charged him with first-degree murder while armed. He was ordered detained until a June 27 preliminary hearing in D.C. Superior Court.

Court documents show that police previously identified two other suspects connected to the robbery, information not previously revealed. One man is being held on several gun charges linked to the shotgun, which police said in court documents was found in his possession. Another man who police said assisted in the robbery has not been charged.

At the time of the attack, authorities said they did not know of a motive. Williams’s relatives said they believed that he was robbed, which is backed up in a detailed account of the killing provided in court documents.

Police said three men were watching, and at one point following, Williams as he walked home from the Deanwood Metro station. Video surveillance cameras show them walking along Lee Street, a block from the victim’s apartment, according to the documents. One man is seen breaking away from the group and taking another path, which police said was intended to cut off the victim and box him in.

Police said the final confrontation occurred at the door leading into Williams’s apartment building.

Williams’s family remembers him as an intelligent, easygoing young man who also was willing to stand up for himself.

“I think that they thought he was going to be an easy mark. It sounds like he was just true to himself, and that was that,” said Kofi Ross Minor, Williams’s sister.

The would-be robbers stole nothing during the incident, Ross Minor said. The family expects to follow the prosecution closely, she said.

“We want the perpetrators to know his life had value,” she said. “We continue to love him and miss him dearly.”

Williams’s pastor, the Rev. Alethea Smith-Withers, said his congregation and family plans to campaign for stronger gun-control measures.

“We’re thankful someone has been arrested, but we realize this is step one,” Smith-Withers said. “We’re thankful for the witness who was courageous enough to come forward.”

Williams had graduated from Catholic University with a bachelor’s degree in interdisciplinary studies and was taking graduate-level courses preparing for law school.

He had been a manager of a shoe store but returned to sales to free up hours for school, his family and minister had said earlier. He was working at Comfort One Shoes at the time of his death. His brother worked at a shoe store across the street, and the two usually commuted together. But relatives said that on the night of March 14, Williams wanted to leave early and took the Metro home.

His father was a Howard University professor, and family members said that Williams grew up listening to public radio and that library books supplanted electronic entertainment. He was a graduate of Wilson High School and enjoyed discussing Henry David Thoreau.