Cumberland County Sheriff Mark Dion received court permission to force feed him starting on Friday, after Nielsen lost 55 pounds on a hunger strike.
Authorities say Neilsen is down to 103 pounds, and there’s concern his vital organs could begin shutting down.
Nielsen stands accused of brutally killing three women at a bed and breakfast in Newry last Labor Day weekend. Authorities say he also killed an Arkansas man who worked there.
Neilsen was committed Wednesday to the Riverview Psychiatric Center in Augusta.
Sheriff Dion says it be days or even weeks before he transferred back to the jail.