Joseph Riga, a former Homicide Bureau commander in the Buffalo Police Department who recently retired as chief of the transit police, will join the Erie County District Attorney’s Office as chief investigator, District Attorney Frank A. Sedita III announced Thursday.

Sedita also tapped John M. Cleary Jr., previously the chief investigator, to head the new District Attorney’s Investigative Task Force, which will use the latest technology to identify and analyze crimes.

Targeted cross-jurisdiction investigations are expected to help solve crimes committed by the same perpetrator in several municipalities.

Sedita wants a collaborative law enforcement effort where analysts from the Erie Crime Analysis Center can spot trends and suspects and turn that information over to task force investigators. The investigators also will work with the state Department of Criminal Justice Services and the Erie Crime Analysis Center.

Cleary is a former state police investigator. District attorney investigator Mark J. Vaughn, a retired city homicide detective, also will be a member of the task force.