WATERLOO - A Des Moines man accused of threatening to blow up a Des Moines air ambulance two years ago has been arrested for setting a fire at the Covenant Medical Center mental health unit.

Covenant staff doused the fire in Observation Room No. 2 before firefighters arrived Monday, said Capt. Mike Jenn with Waterloo Fire Rescue. Fire crews spent about half an hour removing smoke from the area.

Waterloo police arrested a patient, Ajamu Manu El-Amin, 40, of Des Moines, for first-degree arson.

The fire started at about 9:15 a.m. with paper and a bed sheet, according to Waterloo police. Flames spread up one wall before workers were able to extinguish it.

No injuries were reported.

Police said El-Amin was the only person who was in the observation room where the fire started. After the blaze, he handed hospital staff a black cigarette lighter, court records state.

First-degree arson is a Class B felony punishable by up to 25 years in prison.

This isn't the first time El-Amin has been accused of causing trouble for a hospital.

In 2007, he allegedly threatened to blow up a helicopter at Mercy Medical Center in Des Moines, said Sgt. Misti Allison with the Des Moines Police Department.

She said El-Amin got into an argument with Mercy staff over signing papers when he left the hospital in January 2007. He said he would burn or blow up the Mercy One helicopter and later phoned the hospital and repeated the threat, Allison said.

He entered an Alford plea to harassment in that case, not admitting guilt but contending he would likely be convicted if the matter went to trial.

Contact Jeff Reinitz at (319) 291-1578 or jeff.reinitz@wcfcourier.com