Jason Anthony Emma moved to Capitol Hill from Arlington County on Dec. 1, piling into a rowhouse filled with his lifelong friends and excited about living in the city and walking to restaurants, bars and concerts.

But after returning to his new home on C Street in Northeast Washington about 2:15 a.m. Monday, police said the 28-year-old was shot several times, killed as he sat in the driver’s seat of his black Audi just moments after parking.

As D.C. police searched for suspects and a motive, Emma’s family and friends gathered Christmas Eve at his parents’ home, cars lining the street, mourners sobbing on the front steps.

“He wanted to be around the happening place,” said a close friend and roommate who is a D.C. firefighter. “He wanted to be right in the mix of things. . . . He told his parents where he was moving, and they came and saw the house, and they thought it was a very nice place to be.”

Family members said they were too distraught to talk Monday. Emma, the son of a psychiatrist and a graduate of Bishop Denis J. O’Connell Catholic High School in Falls Church, worked from home as an accountant for an online nutrition company while completing coursework at Florida Atlantic University in Boca Raton, the firefighter confirmed.

Authorities said late Monday that they had few clues about Emma’s killing. D.C. police Cmdr. George Kucik, head of the criminal investigation division, said police were looking for two men, one wearing a white T-shirt with dark sleeves, but he conceded that the description was generic and pleaded for witnesses to step forward.

“We are right now seeking information from the public,” Kucik said at an afternoon news conference. “Obviously this is a sad case. . . . We don’t have a lot of information on this.”

The commander declined to elaborate on a possible motive. Police announced a reward of up to $25,000 for tips leading to an arrest and conviction.

The homicide stunned residents in the 1200 block of C Street NE, a quiet corridor of multicolored two-story rowhouses and red-brick sidewalks north of Lincoln Park. The block is home to two churches and a laundromat, lighted Christmas trees are visible through most house windows, and signs advertise a neighborhood watch and a missing tabby cat named Teddy.

The sprawling Capitol Hill neighborhood has been plagued by robberies, car break-ins and burglaries, but shootings and other violent crimes are relatively uncommon. People who lived doors from the spot where Emma was found said they slept through the commotion or were briefly awakened by what they thought were fireworks.

Justin Brookman, 38, said a neighbor told him about the shooting.

“By and large, I feel safe here,” said Brookman as he stood on his front steps. He was receiving family from three states and three countries for Christmas, and he noted that his guests were parking near the site of the shooting — perhaps 50 feet from his front door.

“This is awful,” he said. Brookman said he remains concerned by the August robbery and beating of Thomas Maslin, who was attacked 11 blocks away as he walked home from a bar. Police have made three arrests in that case.

Jennifer Flather, who lives near Emma’s house, said she generally feels safe but senses that crime has crept closer.

“In the last year it’s gotten close to home,” Flather said. “It’s within a few blocks of us instead of six or eight blocks from us. . . . I love it here. I’m sad I will probably look over my shoulder a little more now.”

A lone D.C. police cruiser was parked near the spot of the killing Monday morning.

Nearby, two of Emma’s roommates — including the D.C. firefighter, fresh from an overnight shift and still in uniform — emerged from their house, stunned. They walked up to the scene of the shooting, chatting with the police officer there. Then they went to Emma’s family home in Virginia.

The 27-year-old firefighter, who did not want to use his name because the culprits had not been caught, described Emma as “larger than life” — the type of person to whom everyone gravitated, who returned calls in an instant, who could talk his friends through problems and “come up with solutions.”

“He always had your back,” the man said.

He said Emma loved every minute he spent on Capitol Hill. “We’re surrounded by young professionals,” he said. “We’re surrounded by families. We’re surrounded by people who cared about their community. It hurts to have your community ravaged by a senseless crime.”

“Jason will be missed more than anybody I have missed in my life,” he said. “I’ve lost relatives and other friends. I can’t imagine how we will all recover from this.”

Jennifer Jenkins contributed to this report.