Police were not looking for suspects after responding to the shooting of a 3-year-old girl at an apartment complex in Southeast Washington on Wednesday night. (WUSA9)

One moment, the kids were playing in a second-floor apartment at Benning Terrace. The next moment, D.C. police said, a child had a gun in his hands and it fired, turning innocent summertime play into tragedy when a bullet struck 3-year-old Dalis Cox in the chest.

The girl, who liked bikes, Elmo and playing on her father’s tablet, died at a hospital about 90 minutes after the shooting Wednesday night.

“Her innocence made you forget about all the bad things,” said Tanika Thorne, a family friend.

On Thursday, grieving friends and relatives streamed in and out of the 46th Place SE apartment, on a cul-de-sac encircled by strips of low-rise red-brick buildings. Dalis’s mother remained inside with a counselor.

Visitors, friends and D.C. police were struggling to understand precisely how the shooting occurred and how a child came by the weapon. Dalis’s father, Timothy Cox, 48, who lives in Suitland, Md., said his 7-year-old son, the children’s mother and possibly one of her friends were in the three-bedroom apartment at the time of the shooting. Police said there were children and at least one adult inside.

Dalis Cox (Courtesy of the family)

Two police officials have said they believe that the 7-year-old accidentally shot Dalis and that the gun went off twice.

D.C. Police Chief Cathy L. Lanier said that the gun was not registered and that detectives do not yet know who owned the weapon or how it got into the apartment. She said police are looking at whether criminal charges­ are appropriate.

“We have no reason to believe that it’s anything other than an accident, so what we’re looking at is how the gun got into the house,” Lanier said. “We believe it was a young child that got their hands on a gun.”

Lanier said officers were in the block when the shooting occurred about 8:20 p.m., and heard at least one gunshot and screaming. She said the officers put Dalis in a squad car and sped to the hospital.

“My heart goes out to Dalis and her family,” Mayor Muriel E. Bowser (D) said at an afternoon news conference. “The gun should have never been in a place where it could have been accidentally or otherwise used to put a little girl in danger.”

Thorne said she went to Prince George’s Hospital Center, where Dalis died at 9:50 p.m. “When I reached the emergency room last night,” she said, “I heard Timothy scream out, ‘My baby’s dead.’ ”

Corey Cox, Dalis’s uncle, said it was “senseless the way it’s so easy to get guns.” He visited with Dalis’s mother Thursday afternoon and said family members are trying to piece together what happened.“There was an adult in the house at the time,” he said. “The kids were running around having fun, and then someone was shot.”

Dalis’s mother declined to talk publicly about her daughter or the shooting, and many who visited her Thursday followed suit, asking that they be left alone to mourn. Timothy Cox said Dalis was one of his three children with the girl’s mother; in addition to the 7-year-old, they have a 10-year-old daughter. The family has started a GoFundMe site to raise money online for Dalis’s funeral.

“Dalis was our sweet, precious little girl,” they wrote on the site. “Our hearts are broken.”

Dalis’s great-aunt Mary Rhone, 65, visited Dalis’s mother Thursday. When she walked in the apartment, she said, her niece was crying hysterically and screamed, “Auntie, why did this happen?”

Rhone said that she talked with two of Dalis’s siblings in a video-chat at midday Thursday and that they were doing “fair” given the circumstances. She said she doesn’t think the 7-year-old “even remembers” what happened.

Timothy Cox said he last saw Dalis on Wednesday evening. He went to the mother’s apartment after work to see her as he does many nights. He said he joked, snuggled and played with his daughter on a couch in the apartment. When it was time for him to leave, Dalis got up to get her shoes as well.

“She said, ‘Daddy, I want to come with you,’ ” he said. “I said, ‘Baby, I have to go to work. I will be back to get you the next time.’ ”

Later Wednesday night, Cox said, he got a call from a neighbor saying Dalis had been shot. He rushed to the apartment and then to the hospital.

“Dalis is my life and soul,” said Cox, who works for a transportation company. “I’m at a real loss. People need to make sure they are with their kids at all times. Tomorrow is not promised. . . . She is going to be our angel over us.”

Cox said he did not have any guns in the Benning Terrace apartment. “There shouldn’t be a weapon within a child’s reach,” he said. “Kids don’t understand. That unfortunately cost me my daughter.”

Outside the apartment complex on Thursday, families mourned the little girl who liked to be held and wore braided hair decorated with pink, blue and yellow beads.

Jasmine Gilbert said she and her two young daughters moved from Benning Terrace four months ago, in part to get away from crime. They returned to pay their respects after learning what had happened. Gilbert’s daughters, Zenovia, 2, and Zaniyah, 4, were friends with Dalis.

Gilbert said she was angry about a gun being in the apartment and devastated by Dalis’s death. In trying to explain the girl’s death to Zaniyah, she told her, “Your friend is in heaven.”

Zaniyah didn’t quite understand. She knew she had returned to her old home because of her friend but wondered why Dalis didn’t come out.

“What happened to Dalis?” Zaniyah asked, while standing in front of the apartment building. “I played with her. She was my friend.”

Dana Hedgpeth, Jennifer Jenkins, Clarence Williams and Julie Zauzmer contributed to this report.