VALLEJO, Calif. (KGO) -- Stephanie Bass says her son Eric Reason didn't deserve what happened to him in the parking lot of a Vallejo gas station Sunday night. Reason was shot and killed by an off-duty Richmond police officer."This is so devastating. We're not doing good at all," said Bass as she stood in front of the Valero station where her son died. "I just want justice. I just want to find out what happened, you know-- what happened that he deserved to be shot down like that."The 38-year-old Reason reportedly had some kind of confrontation with the off-duty officer, identified by the East Bay Times as Sgt. Virgil Thomas-a dispute that ended in gunfire.Nearby apartment manager Kim Lynch heard the gunshots and ran to help."There was a tall African American gentleman standing with a gun in his hand and another African American gentleman on the ground, on the street," said Lynch. "I was like what the hell's going on because this guy's still standing here with a gun and he's like I'm an officer, I'm off-duty."Police reportedly found at least two guns at the scene.According to court documents, Thomas was the object of a federal civil rights complaint in 2007, accused of using excessive force and depriving a man of medical care during a 2005 incident at a Richmond gas station. The case was later settled.Monday, family and friends of Reason gathered at the shooting scene to hold a brief prayer vigil.Reason is the father of six children, a local rapper known as "Cheddaman," who works in construction. Stephanie Bass believes her son must not have known Thomas was a police officer."I believe if he would have said he that he was a police officer that my son would not have been arguing back or something," said Bass.Richmond police released a brief statement confirming one of their officers was involved, but not confirming that officer's name.Vallejo police are releasing few details, citing the pending investigation.