The man in his early 30s was found in a Mascoutah parking lot with a gunshot wound to his head Wednesday.
According to the Department of Veterans Affairs, nearly 25 percent of suicides in Missouri involve a veteran. That compares to some states, including Illinois, where the rate is as low as seven percent.
Castro was sentenced Aug. 1 to life in prison plus 1,000 years on his guilty plea to 937 counts including kidnapping and rape.
Experimental program analyzes online posts for warning signs.
Police on Sunday identified the shooter as 44-year-old Laurie Anderson, who died of an apparent self-inflicted gunshot wound on Saturday.
Correctional workers found a 55-year-old inmate for Maryville, Illinois hanging in his jail cell Thursday morning from his underwear.
Officers believe that one of the men shot the other, then turned the gun on himself. A woman reportedly witnessed the shootings.
Police released video Friday night that shows officers finding Kansas City Chiefs linebacker Jovan Belcher asleep in his car just hours before he killed his girlfriend and later shot himself.
Chaplain wants returning Guard members to realize help is available.