Officer Edward Sawicki III was backing up his vehicle about 2:45 a.m. on the 1300 block of South 9th Street when he struck a man, hitting him in the knee. The man, 37, pounded on the trunk of Sawicki's vehicle to alert the off-duty officer that he had hit him. Sawicki got out of his car, pulled up his shirt to display a handgun, and rushed at the man yelling racial epithets and threatening to kill him, said a spokeswoman for the District Attorney's office in a statement.