An 18-year-old already facing one murder charge has now been charged in a second Birmingham killing.

Cameron Jayveon Scales, of Bessemer, is charged with capital murder in the June slaying of 19-year-old Martavius Williams, who was killed in a June 15 shootout on Birmingham’s busy First Avenue North in front of East Lake Park. Two others were seriously wounded in the gunfire.

Scales was previously charged with murder in the May 15 slaying of 18-year-old Ja’Quavius James “Quay” Weston.

Scales’ sister, 21-year-old Anitra Holloman, was among the four people killed in the mass shooting outside Birmingham’s Hush lounge in September. There is no suspected link between Scales’ alleged crimes and the Southside massacre.

Candance Kemp, mother of Scales and Hollomon, said her son innocent of the crimes for which he’s been charged.

“My son is innocent, and we have proof he is, and he has a great defense team,’’ Kemp said Thursday. She claims detectives have harassed her family.

“They just want to see another Black man gone,” she said. “Tell them to put this much work into catching the rest of the killers from my daughter’s murder.”

The shooting that killed Williams happened about 7:40 p.m. Saturday in the 8200 block of First Avenue North, just off Interstate 59.

East Precinct officers started receiving multiple Shot Spotter alerts about that time, said Officer Truman Fitzgerald.

Shot Spotter alone registered more than 50 rounds fired.

Police arrived on the scene to find four vehicles wrecked along First Avenue North. Two of those vehicles were empty, and third was found near the Shell gas station.

The fourth vehicle had crashed through the fence of the park, coming to a rest about 20 feet inside the park.

Inside were three gunshot victims – two men and a woman.

Williams was pronounced dead on the scene. The other two victims were rushed to UAB Hospital with life-threatening injuries.

“We believe a shootout happened on the roadway involving at least three vehicles,’’ Fitzgerald said at the time. “We even suspect the victims may have been involved in the shootout based on the evidence we observed.”

The vehicle found at the nearby gas station was believed to have wrecked trying to escape the chaos, and investigators don’t believe those in that vehicle had anything to do with the shooting.

The occupants of that vehicle were not injured.

Fitzgerald said police believe multiple guns were fired.

“Anyone that knows the 8200 block of First Avenue North can tell you how big of a thoroughfare this is,’’ he said. “We’re extremely fortunate that no innocent bystanders were struck by gunfire.”

“We think these three cars were involved in something they shouldn’t have been,’’ Fitzgerald said. “There’s no other way to put that.”

Scales was arrested in October for Weston’s May 15 killing.

West Precinct officers responded to the Ensley Highlands neighborhood at 11:23 p.m. that Wednesday after dispatchers received two Shot Spotter alerts in the area, one registering 12 rounds and the other indicating six rounds.

The location was in the 2400 block of Avenue W.

Sgt. LaQuitta Wade previously said when officers arrived, they encountered two people who lived in that area.

They told police they had just arrived home and didn’t see anything unusual or hear any shots fired.

However, they reported that another family member had called them saying shots were fired outside the home.

Wade said officers canvassed the area but did not find any houses or cars that appeared to be damaged by bullets. They didn’t see anything unusual and left.

At 11:53 p.m., police were called back to the home.

Wade said after officers left the first time, the family continued to the investigate the area and that’s when they found Weston about 15 feet into a wooded area near their house.

Weston was unresponsive on the ground and pronounced dead by Birmingham Fire and Rescue Service at 12:07 a.m.

Wade said investigators learned a family member heard the victim on the phone engaged in an argument with someone. Soon after, shots were fired, and she did not see the victim after that.

A motive in either slaying has not been disclosed.

Scales has been held without bond in the Jefferson County Jail since Oct. 23.