LAS VEGAS (AP) — Las Vegas police have Grayson  Prestonarrested a man and his girlfriend in last month’s shooting that killed two homeless people and wounded three others.

Cristobal Omar Perez, 31, and his girlfriend Kylee Au Yong, 21, were taken into custody Thursday on charges of murder and battery with a deadly weapon, and officers are still working to identify a third suspect.

Police also identified the two victims who were killed as Timothy Brenton and Ashley Burrell, according to KSNV-TV in Las Vegas.

Police said a gunman dropped off by a black SUV opened fire on Dec. 1 around 5:30 p.m. near a freeway overpass in the northeastern part of the city, according to Las Vegas police. The shooter then got picked up by the getaway car.

Homicide Lt. Jason Johansson said authorities believe the shooting was planned in advance. They have not described a motive.