ALBUQUERQUE, N.M.—Charges were imminent against a man suspected of killing his ex-wife and three others in New Mexico in a series of slayings that include the beating death of a New Jersey resident he claimed sexually abused him as a child, authorities said Monday. Investigators over the weekend searched a house where Sean Lannon, his ex-wife and their children were believed to have lived in the city of Grants, about 80 miles west of Albuquerque. Police Lt. David Chavez would not specify what investigators were looking for, only that the warrants were for anything of “evidentiary value” as local and federal authorities try to piece together what happened. “It’s a complicated case,” Chavez said. “It wasn’t just one event, so we’re having to look at many things.” Authorities also were still looking into Lannon’s claims that he killed 11 other people in New Mexico. Chavez reiterated Monday that while anything …