Why FBI Won't Give Up the Search for Fugitive Robert Fisher Arizona father accused of killing wife and children, setting home on fire.

April 11, 2014 -- The manhunt for Robert Fisher, the Arizona father accused of killing his wife and children and then blowing up their house, entered its thirteenth year this week, and agents in the FBI's Phoenix office still haven't forgotten the most wanted fugitive's face.

"This man stood over his children, slit their throats so deeply he almost decapitated them and also slit the throat of his wife and shot her in the head," case agent Robert Caldwell said in a statement about the fugitive, who if alive, would be 52 years old.

"We never let off the gas pedal. Even after 13 years, we still have not let off the pedal. We are going to continue to look for him until he is brought into custody," he said.

Mary Fisher, 38, and their two children, Brittney, 13, and Bobby, 10, were killed inside their Scottsdale, Ariz. home on April 10, 2001.

Caldwell said an accelerant was poured over their bodies and down the hallway of the home, which was then rigged to explode.

Fisher was officially named a suspect on April 14, 2001.

The callous crime captivated Arizonans, who reported possible sightings of the suspect authorities described as physically fit and an avid outdoorsman.

Fisher’s Toyota 4Runner and dog were found in the woods about 80 miles away in Arizona several days after his family was murdered. It was the last clue to the surgical catheter technician's whereabouts.

Since then, tips have poured in that Fisher was relaxing at an upscale San Diego hotel, hiding out in caves and had started a new life in Canada.

Authorities held a Fisher lookalike in Canada in 2003 until it was confirmed they had the wrong man.

There's also the theory that he killed himself, but Caldwell said the man who was described as arrogant and hard to get along with, likely didn't take his own life.

Fisher should be considered armed and dangerous. Anyone with information about his whereabouts is asked to contact their local FBI office or American Embassy or Consulate.