Investigators believe Lionel Clyde Purkey, 56, fatally shot his friend, Ronald William Johnson, 47, around 9:20 p.m. Friday after a brief disagreement inside a home in the 4700 block of Thorpe Road.
Purkey then shot himself, sheriff's Officer Paula Toynbee said. Solano County coroner's deputy Adrian Garcia said Johnson lived in a trailer on Purkey's property.
Garcia said both men were shot at least once in the chest with a shotgun.
The sheriff's office said Purkey's son was home at the time of the shootings and called the sheriff's department at 9:21 p.m.
The incident is still under investigation, Toynbee said.