Convicted penny-stock spammer Eddie Davidson has died of a self-inflicted gunshot wound, apparently after killing his wife and three year-old daughter in his home town of Bennet, Colorado, the U.S. Department of Justice said Thursday.

Davidson had been a fugitive from the law since walking away from a federal minimum-security prison camp in Florence, Colorado, on Sunday. He had been serving a 21-month sentence after pleading guilty to criminal spam charges late last year.

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Another person, a teenaged girl according to local reports, was shot, but survived the incident. Authorities also found an infant, unharmed, at the scene of the shooting.

Davidson's wife had been in the car with him when he left the Florence prison, about 45 miles south of Colorado Springs, on Sunday. He had last been seen in Lakewood, Colorado, where he got a change of clothes and cash, according to the Department of Justice.

Known as the Colorado "Spam King," Davidson earned millions of dollars between 2003 and 2006 by operating a spamming operation, called Power Promoters, out of his home. He would change the header information in his messages to make it appear as if they had come from legitimate companies such as AOL and then send them out to hundreds of thousands of addresses.

Davidson sent the messages on behalf of an unnamed Houston company, court filings state. He was asked to promote about 19 penny-stock companies, including one called Advanced Power Line Technologies in 2006 and 2007. He would earn fees based on the trading volume of the stocks he was promoting.

The business was lucrative: The Houston company paid Davidson about $1.4 million for his services, court documents state.

Between 2003 and 2006, when his primary source of income was spam, bank account deposits into Davidson's account totalled about $3.5 million.

"What a nightmare, and such a coward," said U.S. Attorney Troy Eid in an e-mailed statement. "Davidson imposed the 'death penalty' on family members for his own crime."