LOS ANGELES — A Los Angeles computer security consultant has been sentenced to four years in federal prison for using malicious software that turned thousands of computers into "zombies" so he could steal private information.

Prosecutors say 27-year-old John Schiefer was sentenced Wednesday after pleading guilty last April to computer fraud.

Prosecutors say Schiefer and his associates created "botnets" -- armies of infected computers -- to steal individuals' identities by extracting information from their personal computers.

Schiefer also worked as a consultant with a Dutch Internet advertising company to defraud it with his botnets. He was ordered to pay $19,000 in restitution to PayPal and other companies.