AURORA, Colo. (AP) — Police in the Denver suburb of Aurora have arrested three teenagers in connection with the shooting of three students in a high school parking lot on Friday, a Colorado newspaper reported Monday. A television station quoted the city’s police chief as saying gang involvement was suspected.

Police arrested one 16-year-old boy late Friday and two more 16-year-old boys on Sunday, Sentinel Colorado reported. All face charges of first-degree attempted murder.

Friday’s shooting at Hinkley High School injured two boys, ages 16 and 17, and a 17-year-old girl, police said. None of the injuries was life-threatening and the suspects and victims have not been identified.

The shooting came four days after six students from another school in the same Denver suburb, Aurora Central High School, were wounded by bullets fired from at least one car driving by a park near the school. Police have not arrested anyone yet in the earlier shootings. The two schools are 3 miles apart.

Aurora Police Chief Vanessa Williams said Sunday that it appeared the two shootings were not connected, KDVR-TV reported, and that investigators believe there was gang involvement in the Hinkley shooting.

“It doesn’t look like the Hinkley shooting is connected to the Central shooting, so we have a problem,” Wilson said. “There is a gang nexus to this Hinkley shooting.”

She also issued a warning to criminals: “For those who didn’t care and just shoot in the middle of the day, while kids were returning from lunch, we’re coming for you, we are.”