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Investigators haven't released the motive in the slaying of Raymond Casso or details about what happened, U.S. Postal Inspection Service spokesman Jeff Fitch said.
All they have said is that Casso was killed at about 11 a.m. inside the post office at 6150 Center St. and that 37-year-old Concord resident Shannon Bradley Moore has been arrested on suspicion of murder.
Moore is at Contra Costa County Jail in Martinez Monday with his bail set at $1 million, according to a jail official.
Longtime friend and fellow Concord/Clayton Valley Sunrise Rotary Club member Chuck Graham said the community was still in shock over the slaying. Casso left behind a wife, three children and four grandchildren.
"He was a very jovial man," Graham said. "He just enjoyed life."
Casso had owned a rubber stamp business, but was semi-retired and spent time volunteering in the community.
"He was a bell ringer last Christmas for the Salvation Army and helped raise a lot of money," Graham said.
A Clayton police officer said the killing was the city's first homicide in 13 years, according to Fitch.
The post office reopened Monday morning, according to an employee.
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