Baltimore police arrested a teenager in connection with Sunday’s mass shooting.

City police announced late Friday morning an arrest of a 17-year-old boy.

Police said detectives believe the 17-year-old boy was involved in the mass shooting. He remains held at Central Booking on charges of possession of a firearm by a minor, assault weapon possession, reckless endangerment and handgun in vehicle. Police said they executed a search warrant on a house.

Three victims remain at hospitals, all in fair condition.

This is still an open and ongoing investigation.

Anyone with information is urged to call police at 410-396-2100 or Metro Crime Stoppers at 866-7LOCKUP. There is up to a $28,000 reward for any information that leads to an arrest and charges.

There’s much healing that needs to take place in the south Baltimore community after 30 people were shot at a block party. Two of the victims — 18-year-old Aaliyah Gonzalez and 20-year-old Kylis Fagbemi — died.

Residents told 11 News they’re uncomfortable and concerned after such a traumatic shooting, and on top of that, many are fearful because the shooters haven’t been caught.

Metro Crime Stoppers, with support from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, is offering a $28,000 reward for information leading to the arrest and conviction of the people responsible for the shooting. Anyone with information is asked to call 911 or Metro Crime Stoppers at 866-7LOCKUP.

Of the many services being offered at the Brooklyn Homes Community Center, mental health is one of the most critical.

“I’ve been loving the openness to say, ‘I need someone to talk to. I need therapy right now.’ We’ve had individuals that were directly impacted who have come in,” said Cyrus Nusom, the director of outreach and operations at Transformational Health. “But then, the indirect people, some of the people that are telling us that their children will not leave their homes right now, those people need help.”

Mental health professionals with Transformational Health told 11 News that they answered the call Sunday afternoon to bring resources to the families who are dealing with trauma — whether they were there at the time of the shooting or even blocks away.

“When there is trauma — whether you live directly in what we call ‘ground zero’ or you live four blocks over — the impact is real, trauma is real, trauma response is important. That’s why we had to be here,” Nusom said.

Nusom told 11 News they’ve dealt with two crises, provided on-the-spot care for 10 people and signed up more than 100 others for therapy. Nusom said one man came running in asking for help.

“He was trembling, and the No. 1 thing he kept saying was, ‘I’ve never experienced anything like this. I’ve been living out here for about 10 years,'” Nusom said. “This young man, who said he was about 39, he was in fear for life and his child.”

Nusom said several people were coming back to sign up family members, especially children.

“If I had a child in my home, I would drag them up to this community center to have somebody speak to them,” Nusom said.