A man riding in a car with his cousin shot and killed another passenger then returned to the same neighborhood near Orlando hours later and shot four more people, killing a journalist covering the original shooting and a 9-year-old girl, Florida police and witnesses said.

Orange County Sheriff John Mina characterized the shootings Wednesday as random acts of violence. Mina said during a news conference that 19-year-old Keith Melvin Moses has been arrested and charged with first-degree murder in the initial shooting that killed Nathacha Augustin, 38, and that “numerous more charges” would follow.

Spectrum News 13 identified the slain reporter as Dylan Lyons. Photographer Jesse Walden was also wounded. Mina said Walden has been talking to investigators while being treated at a hospital.

The two were in an unmarked news vehicle on Wednesday afternoon covering the first homicide when a man approached and shot them, Mina said. The man then went to a nearby home where he fatally shot T’yonna Major and critically wounded the girl’s mother. Officials have not released the mother’s name.

Mina said Thursday that investigators do not know the motive for any of the shootings. He said Moses is a known gang member but that the shootings didn’t appear to be gang-related. It was not clear if Moses knew that two of the victims were journalists and Mina noted that their vehicle didn’t look like a typical news van or feature the station’s logo.

The sheriff said when deputies arrested Moses they seized a Glock semiautomatic weapon that “was still hot to the touch, meaning it had just been fired, and there were no more rounds.”