Colorado authorities said Davidson killed his wife and 3-year-old daughter before killing himself. All three died of gunshot wounds.
Davidson was in the news earlier in the week when he escaped from prison after his wife came to visit him last Sunday.
Authorities were called to the scene, a residential neighborhood in Lakewood, Colo., at 11:15 a.m. Thursday and found the bodies of Davidson and his wife in the driveway and the daughter in a parked SUV. An infant boy was found alive in the vehicle, and was taken to a local hospital for treatment for dehydration, officials said.
Davidson was sentenced in April 2008 to serve 21 months and pay more than $714,000 in restitution following his conviction of sending spam e-mails. In his plea agreement, Davidson admitted he operated a Colorado business called Power promoters, which provided promotional services for companies by sending spam between July 5, 2002, and April 15, 2007. The Colorado attorney general's office said Davidson was one of the state's largest Internet spammers.