In a police statement, Diamond is quoted as saying he continued shooting at Guadalupe until he "stopped moving."
They were shot in the parking lot of a Simon & Schuster book warehouse about 20 miles north of Philadelphia, where he had been fired months earlier.
Diamond had been fired a few weeks before the shootings.
A psychiatrist testified that Diamond has been mentally ill most of his life.
During the investigation, Action News has obtained documents detailing what police found when they searched Diamond's home and his car.
They say that in his car they found a book that was titled 'Black Power'.
The documents also say that Diamond, who is white, told them that he only purchased the book to better understand the people at work who he believed were trying to persecute him.
In a statement Diamond told police he felt persecuted at work for a run-in with another employee. The D.A. believes Woodson, a shop steward, was specifically targeted, and that Guadalupe just happened to be there when the gunfire began.
Michelle Henry, Bucks County District Attorney told reporters, "He went there in broad daylight at 3:30 in the afternoon, when the shift was ended. He had previously worked that shift, and so he was aware of what time the employees would be leaving that company, and he waited for them."
Authorities say Diamond intended to kill, and didn't seem worried about getting caught.
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