Mugshot of 40-year-old James Dale Ritchie. Ritchie was posthumously determined by police to be responsible for five killings over the course of last summer. (Photo courtesy of Anchorage Police Department)Police in Anchorage say they’ve determined that a single person was responsible for a wave of killings over the summer.Listen nowIn a statement today, the department said homicide detectives have “sufficient probable cause” to conclude James Dale Ritchie murdered five people picked largely at random with the same gun. Ritchie died during an early morning shoot out with an APD officer in November after a routine stop on a downtown street.APD says Ritchie is suspected in the homicides because of his ownership of a Colt .357 Python revolver used in all five murders.Both the APD and FBI refused to comment further today on the case. Neither agency will say whether Richie is thought to have committed other homicides, specifically how they reached the conclusion that he committed all five homicides and whether there will be any follow up.In a statement, APD spokesperson Renee Oistad said APD and the FBI do not want to discuss or compromise their investigative techniques.The investigation involved multiple law enforcement agencies as well as a huge effort to gather information from the public.For months, police and elected officials in Anchorage declined to say whether a rash of random overnight killings were connected. Two victims were found by a trail near Post Road. One young man was shot riding his bike on the East side of town. And in August, another two victims were discovered near one another on a popular stretch of trail in Valley of the Moon park.