SCOTTSDALE, AZ - On the morning of April 10, 2001 fire crews responded to a home explosion in Scottsdale.
Just as the smoke began to clear, the fire investigation turned into a murder investigation and the man at the center of it was nowhere to be found.
Robert William Fisher remains at the top of the FBI's Ten Most Wanted list and federal agents believe he has taken on a new life as he avoids authorities.
Investigators say on the night of April 9, 2001 Fisher and his wife Mary got into an argument. It's believed Mary informed Robert that she was thinking about divorcing him.
Hours later, detectives determined Robert shot Mary in the head and cut her throat. It's believed Fisher then went into his children's bedroom, approaching 12-year-old Britteny and 10-year-old Bobby Jr. and killed them by slicing their necks.
Following the murders, investigators say Fisher spent the next few hours packing up some belongings, disconnected a gas furnace and lit a candle.
The candle would act as a timing device allowing gas to build up in the home.
Around 8:30 on the morning of April 10, 2001 Scottsdale police and fire crews responded to the home after reports that it had exploded.
Investigators found the three bodies and immediately started searching for Fisher.
He hasn't been seen since.
"This case is definitely still progressing," said FBI Special Agent Robert Caldwell.
Everyday, Caldwell, who is the case agent assigned to tracking down Fisher, says he receives reports of possible sightings of Fisher.
"I do get calls and/or tips every day from all over the country, even the world. Just a couple of days ago I got a report of a sighting in Guatemala," said Caldwell while sitting in a Phoenix FBI office with photos of Fisher on his desk.
Caldwell says he's received tips from virtually every corner of the United States.
"Aside from Mexico, we had a lot of sightings in Louisiana, the east coast, the west coast, who knows he (Fisher) is even arrogant enough to possibly be hiding out or living somewhere here in Arizona," Caldwell said.
Special Agent Caldwell has been with the FBI for nearly 20 years and has spent half of his career chasing Fisher.
"Is it one of my most important cases? Absolutely it is," said Caldwell. "I get asked all the time if I think Fisher is still alive and you know what, we won't know until we either find his body or find him alive walking around some place."
The last trace of Robert Fisher came 10 days after the murders and explosions.
His image was captured on an ATM and then his wife's SUV was found in the Tonto National Forest about 100 miles from the crime scene in Scottsdale.
"And inside (the SUV) was a coffee mug and the Oakland Raiders ballcap that Robert Fisher was wearing in the ATM photo, after that we haven't had a confirmed sighting since," Caldwell said.
Some believe Fisher took up residence in a cave, others believe he had a getaway car waiting and drove away starting a new life.
"It's a challenging issue in this case locating him because Robert Fisher has such a common look if you will, he looks like a lot of people," said Caldwell.
Fisher is an avid outdoorsman and known as a good hunter and fisherman. The six foot tall 190 pound physically fit man has a surgical scar on his lower back.
Investigators say another feature that stands out with Fisher is that he walks with an exaggerated posture. Due to back surgery, Fisher walks with a stiff posture with his chest sticking out.
At times over the years, Caldwell says he and other agents thought they were close to nabbing Fisher, only to find out they were incorrect after taking people into custody.
"We've had them up to the point where we've actually run their fingerprints to make sure it wasn't him (Fisher)."
Over the past decade, Caldwell estimates the FBI has received thousands of tips and encourages people to call 911 if they think they see Fisher.
"He's armed, we know guns were missing from the home, and we know he was known for carrying a gun on him and he is very dangerous," Caldwell said. "We want people to call 911 immediately, this is something we would need to act fast if someone thinks they see him."
Even though it's been 10 years, Caldwell says he has no problem maintaining his focus on the search for Robert William Fisher.
"It's self motivating, this is a person who doesn't deserve to be walking the streets like you and I," Caldwell said. "One day it will be a great victory when we do find him."
Copyright 2011 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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