WESTMINSTER, Colo. — A 23-year-old man has been arrested and booked into jail on suspicion of murder in a quadruple shooting outside a dental office that left a boy dead in what appears to be a case of road rage, the Westminster Police Department said Friday.

Jeremy Webster was booked into the Adams County jail early Friday morning and is being held for investigation of first-degree murder after deliberation with intent, first-degree murder extreme indifference, first-degree assault and criminal attempt to commit a Class 1 felony.

The boy was pronounced dead, and his mother and brother suffered life-threatening injuries in the shooting about 3 p.m. Thursday in the Cedar Wood Square parking lot near West 80th Avenue and Sheridan Boulevard.

The mother and boy who were wounded were in critical condition as of Friday afternoon, police said. The family issued a statement requesting privacy.

Another man also was shot but is expected to survive his injuries, police said.

Webster admitted to shooting the four people, according to a court document obtained Friday.

Webster fled the scene but was taken into custody about three hours after the shooting when the Colorado State Patrol intercepted his vehicle on Interstate 25 near Castle Rock.

The victims have no relationship with Webster, police said.