WATERBURY, Conn. -- The Waterbury Police Department said Saturday it is investigating a crash that left a K-9 officer dead and sent three people to the hospital.

They said the crash happened at about 3 a.m. at the intersection of Highland Avenue and Highland Drive.

Officer Matthew Smith, a five-year veteran of the Waterbury Police Department, was traveling east across Highland Avenue from Highland Drive to Vail Street when his police cruiser was struck by a 1994 Cadillac Seville traveling north on Highland Avenue.

Micah Bonacassio, 19, of Thomaston, was driving the Cadillac with Jason Giordano, 22, of Watertown, when he hit Smith's cruiser. The impact killed a K-9 officer, Domino, and left Smith and Giordano in stable condition at Waterbury Hospital and Bonacassio in stable condition at St. Mary's Hospital.

No charges have been filed and the accident remains under investigation.