KENNEWICK, Wash. (AP) — Officials say an autopsy to determine the cause of death of a 19-year-old mentally ill man who died at the Benton County jail did not reveal a cause.

The Tri-City Herald reports further testing is needed to determine how Marc Anthony Moreno died in his single-person cell Friday, about a week after his arrest on misdemeanor warrants.

His family says he was arrested while seeking counseling at the Benton Franklin Crisis Response Unit in Kennewick. His family protested his death at the Benton County Justice Center Monday and demanded answers.

A special investigation unit is investing the case. Suicide is not suspected. Moreno's family says he was bipolar and suffered from schizophrenia.

The Benton County Sheriff's Office says Moreno was uncooperative during his arrest and when he arrived at jail. It says corrections officers never used force on him.

Sheriff Steve Keane says Moreno acted erratic, refused to eat for several days and barely slept. Keane says mental health professionals assessed him daily and jail staff checked on him every 30 minutes.