BLISSFIELD, Mich. (AP) -- Police say they don't have any indication of where to find an Ohio man charged with murder in the shootings of his ex-girlfriend and her pregnant sister in Michigan.

Michigan State Police Lt. Sean Furlong says the U.S. Marshals Service is working Tuesday with state authorities on the nationwide search for 38-year-old Thomas Fritz of Sylvania. Police are seeking tips about his whereabouts.

Fritz also is charged with one count of assault with intent to commit murder after authorities say he wounded the sisters' mother in the Friday shooting in Blissfield, 20 miles northwest of Toledo, Ohio.

Police say he killed 33-year-old Amy Merrill, who was his ex-girlfriend, and 24-year-old Lisa Gritzmaker, who was about 8 months pregnant. Police say 52-year-old Robin Lynn McCowan is recovering Tuesday at a hospital.