"Apparently the package arrived on the 1st of February. It was not opened by me. I did not know of its existence until today," Cooper said Thursday.
Cooper said the package contained a bullet-riddled coin that was wrapped in duct tape. The tape had a handwritten message that said, "Thanks, but no thanks Will Bratton," referring to former Los Angeles police chief William Bratton. The coin is typically handed out by the police chief as a memento.
The package also had a hand-labeled DVD and a note that read, in part, 'I never lied.' According to the LAPD, Dorner was fired because he lied about an incident back in 2007 when he was a rookie cop working alongside a training officer.
Dorner filed a lawsuit in an effort to try to keep his job, but that lawsuit was rejected, and so was his appeal. That chain of events appears to have triggered Dorner's alleged revenge rampage.
Authorities say Dorner wrote a multi-page manifesto in which he threatened to kill law enforcement officials. He is wanted in connection with a double murder in Irvine and the shootings of three police officers on Thursday.
Law enforcement officials are inspecting the package for clues.