The firefighter accused of killing his wife with an ax after allegedly learning she was cheating pleaded not guilty in a Los Angeles courtroom Wednesday as family and friends of the slain woman showed up in force. Glendale fireman Andrew Jimenez, 45, has been charged with the domestic violence murder of his wife, Mayra Jimenez, 46, after she was found bludgeoned to death  in the couple’s North Hollywood home on Jan. 21. The firefighter is accused of using an ax to commit the brutal alleged