CLEVELAND -- Joseph Newton Chandler died twice. First in Texas 70 years ago, at the age of 9. Then, here in Northeast Ohio in 2002 at age 65.

It's a cold case that has puzzled U.S. Marshals for a decade. The man found dead in his Eastlake apartment stole the identity of the dead boy from Texas. That much is clear. But who he was, and why he did it remain a mystery.

"You don't just assume the identity of a deceased 9-year-old boy and live that life throughout your lifetime. He was running from something," said U.S. Marshal Pete Elliot.

The mystery of Joseph Newton Chandler ranks among Northeast Ohio's most perplexing unsolved cases, right after the disappearance of Amy Milhaljevic and Beverly Potts.

"I can't say what that thing was he was running from. But I would suspect, based on my experiences, it's something that was pretty bad in the past," added Elliot.

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Records show the real Joseph Chandler lived with his parents. They died in a car accident in Sherman, Texas in 1945 while on their way to visit family.

In 1978, the mystery man used Joey's personal information to obtain a Social Security card in Rapid City, South Dakota. Not long after, he moved to Ohio, began working at Lubrizol and keeping to himself.

We caught up with a former co-worker who recalled the man as "odd."

"Joe was very shy," said Mark Herendeen. "He didn't want to be bothered by anybody. He didn't want to talk to other people. He was pretty deep into what he had to do for work."

It was only in death that the man who posed as Chandler stood out.

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In July of 2002, Chandler went to his apartment and using a gun, took his own life. Medical reports indicate the man had been diagnosed with cancer, but it's not known if declining health was a factor in his suicide.

When police tried to contact the dead man's next of kin, his web of lies started unraveling.

"He was living right here for that many amount of years under somebody else's name, and nobody can figure out why," said Elliot.

There are some theories about Chandler's true identity.

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The most popular among Internet sleuths is that of the Zodiac Killer, who taunted and terrorized Northern California in the 1960s and 1970s. Both men had a knack for electrical engineering.

Mark Herendeen remembers a device that Chandler created to block out noise at work.

"Anytime other background noise was bothering him, he had this device and it was wired through ear phones and it had a wire down into his pocket," said Herendeen. "And he had a little device in his pocket that he built, and he would just push it and you would hear white noise."

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Some investigators also put Chandler in California around the time of the Zodiac murders. But this lead seems to go cold.

"There was a lot of speculation on the Internet and so on and so on, that he looked and resembled the Zodiac Killer. We're not ruling anyone out because we just don't know," said Elliot.

Another Internet theory, Chandler was Stephen Campbell, a Cheyenne, Wyoming engineer wanted for attempted murder. The list goes on and on, but for Pete Elliot one thing is certain.

"The guy was a ghost," said Elliot. "At this point, we have no idea who he was."

Elliot says he's looked at possible leads from all around the country outside U.S. borders too, such as Australia and British Columbia. Elliot admits investigators have even looked into Nazi war criminals who have disappeared.

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