CHICAGO (CBS) — Arrested with a gun as he was fleeing the scene of a mass shooting in Englewood early Sunday, Marciano White told police he hid in a closet as the shots rang out, and found a revolver on the stairs as he was leaving, but authorities are awaiting ballistics and gunshot residue tests as they investigate.

White, 37, is charged with unlawful use of a weapon and being an armed habitual criminal. During a bond hearing Monday afternoon, a judge set his bail at $300,000.

Because he had the loaded weapon as a convicted felon, White was charged with a Class X felony, CBS 2’s Chris Tye reported.

Police and prosecutors have said 13 people were wounded early Sunday, when at least two people started “shooting randomly” at a memorial party for 22-year-old Lonell Irvin, who was shot and killed when he tried to carjack a 41-year-old man in April.

RELATED: Englewood Residents Look To Faith, Call For Unity After 13 Are Shot At Memorial Party

Chicago Police Chief of Patrol Fred Waller said dozens of officers were called to the house near 57th and May streets around 12:30 a.m.

“The whole house is going to be a crime scene. The whole house,” an officer was heard saying over police radio. “There’s blood everywhere.”

After a quarrel at the party, someone started shooting inside the house, Waller said. As people were fleeing the house, at least one of those people started shooting at others who were running outside.

“It looks like they were just shooting randomly at people as they exited the party,” Waller said.

One other person who left the house also started shooting at a vehicle as it was driving by the house.

Waller said it was unclear how many people were shooting inside the house, but said police surveillance cameras recorded two people firing shots outside the home.

Police and prosecutors said officers responding to the shooting saw White quickly leaving the site with a bag against his body. The officers tried to pat him down, and when he would not let go of the bag, officers patted down the bag and felt a gun inside. When they checked inside, they found a .357-caliber Mangnum revolver, loaded with five live rounds and one spent casing.

Officers arrested White, who later said he’d been at the party with his girlfriend, and hid in a closet as shots rang out after he’d heard someone had a gun, according to prosecutors.

White told police, as he was leaving, he found the handgun on the stairs and picked it up “out of fear of the situation and the neighborhood,” Assistant State’s Attorney Jim Murphy said.

White has not been charged in the shooting itself, but prosecutors said ballistics tests on the gun and gunshot residue tests on White were pending Monday afternoon. He has past convictions for manufacturing and possession of controlled substances, but defense attorneys stressed he has no violent criminal history.

Meanwhile, there have been no new arrests and there are precious few leads.

Next steps for investigators will be a heavy task. As ballistics tests proceed, there have been no new arrests and there are precious few leads.

Of the 13 people wounded in the shooting, police said two were in critical condition and one was in serious condition as of Sunday afternoon.

Mayor Lori Lightfoot visited several of the victims at the hospital on Sunday, and was furious about the incident.

“It’s a terrible tragedy, and frankly an incredible act of cowardice. People were gathered in commemoration of the anniversary of the birth of someone who was killed earlier this year,” she said.

Lightfoot said she is asking anyone who was at the party to “step up and let their faith overcome their fear” and tell police what they know about the shooting.

“People in that house know what happened, and we have urged them to overcome their fears, and come forward with information so that the police can do their job in tracking down the people responsible for this terrible act of cowardice,” she said. “Some people may not know exactly what happened, but somebody inside that room knows exactly who the shooters were, and we need them to step forward and provide that information.”

A vigil was held for the victims Monday night. There was also a call for anyone with information to come forward.