Three residents of a youth halfway house in Brighton, as well as another man, were arrested after an employee of that home told police a gun was fired there Tuesday morning.

Jan Luis Santiago-Morales, 18, of Brighton, was arrested and charged with unlawful possession of a firearm and ammunition, discharging a firearm within 500 feet of a building and possession with intent to distribute a class B substance after police say they recovered 19 plastic bags of suspected crack cocaine in a jacket belonging to him.

Santiago-Morales was the only resident of the home at 64 Brooks Street in Brighton, a youth group home run by Communities for People, when an employee heard “a loud bang” and found a bullet hole in Santiago-Morales’ upper-story bedroom, according to the police report.

The employee called in to 911 at 10:19 a.m. reporting that earlier that morning he had heard the bang, ran up the stairs to investigate, bumped into Santiago-Morales as the latter was running down the stairs, smelled gunpowder in the bedroom and found a hole in the wall he believed to be a bullet hole.

The police agreed, but a pat frisk of Santiago-Morales turned up nothing and he told them he had heard the bang but didn’t know what it was.

Footage from the house’s Ring security camera at the front door, however, told a different story, according to the police report: Santiago-Morales running out with his hand at his waistband, heading left off the porch and then returning a minute later with his hands “free and clear.” Two other residents, however, were also caught on camera going to the area Santiago-Morales had been and then departing.

Police put out the suspect’s descriptions and a little before 11:30 a.m., thanks to the court-mandated GPS ankle monitor worn by one, police found them exiting a home on Elder Street near the intersection with Eastman Street in Dorchester and entering a red 2003 Dodge Neon. Police stopped the vehicle.

The driver, Geremia Romain Knights, 23, of Taunton, allegedly attempted to flee but was stopped. Police say they found a loaded Smith and Wesson 9mm pistol on him, according to the second police report, which details the Dorchester arrests. The police say a second pistol, another Smith and Wesson, was found in the vehicle under the front passenger seat.

There were four passengers, two of whom, Javeon Phillips, 20, of Boston, and a 17-year-old male, were the two other residents of the Brighton home seen on the Ring camera footage, according to police. They were each arrested. The other two passengers were released.

Knight was charged with unlawful possession of a firearm and ammunition and unlawful possession of a large capacity feeding device. Phillips was charged with unlawful possession of a firearm and ammunition and for a parole violation. The juvenile male was charged with a parole violation.

Communities for People LLC, the operator of the Brighton DYS home, is a Massachusetts Department of Youth Services (DYS) contractor that among its services provides, its website states, group home programs for “children and youth as young as thirteen and up to their 22nd birthday” who had been sentenced in juvenile court.