Robert William Fisher, 58, is wanted for allegedly killing his wife and two young children, then blowing up the house in which they all lived in Scottsdale, Ariz., in April 2001.

The FBI is offering a reward of up to $100,000 for information leading directly to the arrest of Fisher, who is wanted by the FBI for Unlawful Flight to Avoid Prosecution.

The Brooklyn, N.Y, native has brown hair and blue eyes. He is described as a white male who is 6 feet tall and weighs 190 pounds. He has a medium build and a light complexion, with occupations that have included surgical catheter technician, respiratory therapist and firefighter.

Fisher has surgical scars on his lower back. FBI officials say he is physically fit and an avid outdoorsman, hunter, and fisherman. He has a noticeable gold crown on his upper left first bicuspid tooth and may walk with an exaggerated erect posture and his chest pushed out due to a lower back injury. Fisher is known to chew tobacco heavily. He has ties to New Mexico and Florida.

Fisher is believed to be in possession of several weapons, including a high-powered rifle. He should be considered armed and extremely dangerous, FBI officials say.