The suicide of four male patients at the state's mental hospital over the past 18 months has sparked an investigation.

All of the deaths at the Colorado Mental Health Institute occurred in the hospital's 88-bed maximum-security forensic unit, where the most violent, aggressive patients are housed. The patients died between March 26, 1997, and June 16, 1998,"We're very, very concerned," said Steve Schoenmakers, assistant superintendent at the hospital. "This is certainly higher than we would want to see."

The men who killed themselves had all been sent to the facility by Colorado judges either to be evaluated for mental competency before trial or after they were found not guilty by reason of insanity or found incompetent to stand trial.