UnitedHealthcare CEO killing latest: Mangione's mother filed November missing report

Luigi Mangione's mother filed a missing persons report about her son in San Francisco on Nov. 18 -- 16 days before he allegedly shot dead UnitedHealthcare CEO Brian Thompson in New York City -- law enforcement sources told ABC News.

Mangione appeared in court in Pennsylvania on Monday, shortly after his arrest at a McDonald's restaurant in Altoona, Pennsylvania, following a five-day manhunt across multiple states. Mangione told a judge he was in touch with his family "until recently."

Law enforcement sources told ABC News that Mangione's mother spoke with a task force of FBI agents and New York Police Department detectives one day before her son's arrest on Dec. 9.