Mose said she believed Allman "was just pushed over the edge, he really was. I guess he decided to just take things into his own hands."
Another friend, Walter Wilson, board member of the African American Community Service Agency in San Jose, said, "Shareef felt that there was some discrimination on that job, but I had the impression he had it under control."
Wilson said Allman told him he thought the quarry company was targeting older employees who had seniority for layoffs so it could hire cheaper, younger workers at half the wages.
"He also felt that he encountered discrimination because he was the only black person in the job that he had," Wilson said. "He applied for a supervisor job and they gave it to a person with less experience than him, who was not African American. Shareef thought that maybe they didn't like black folks."
The local head of Allman's union said the driver had just come off of a three-week suspension for hitting a wire on the job with his truck.
"We talked last Friday and he didn't seem to be angry about the suspension," said Bill Hoyt, secretary-treasurer of Teamster Local 287. "He told me he thought he was done wrong, and then there were a couple of things said and we actually laughed."
Hoyt said Allman had also had conflicts with his company in the past over working hours. He said the union hasn't made any conclusions about whether Allman was experiencing racial or age discrimination, but that it would be seeking information.
"There are people up there who have 10 or more years on him, so I'm not sure to what make of the age thing," Hoyt said.
A spokesman for the Lehigh cement plant said the company was crafting a statement about Allman and the shootings, but that it won't go into great detail about his work record.
"There are a lot of issues we still need to sort through, so we won't be offering much on this gentleman's history at the plant," said spokesman Nick Rangel.
The quarry victims were shot during a routine workplace safety meeting. Co-worker Shaffer said Allman had repeatedly yelled, "You think you can f-- with me?" as he shot his victims with a handgun and an assault rifle.
Killed were Mark Munoz, 59, of San Jose, Manuel Pinon, 48, of Newman (Stanislaus County) and John Vallejos, 51, of San Jose. Six other men, including Vallejos' brother, Jesse Vallejos, 52, of Gilroy were wounded.