LOS ANGELES — Two New York teenagers were in police custody Wednesday facing illegal computer access and attempted extortion charges after they allegedly threatened to shake down the popular Web site MySpace.com unless its operators paid them $150,000, prosecutors said.

Shaun Harrison, 18, and Saverio Mondelli, 19, of Suffolk County, N.Y. allegedly hacked into the social networking site and stole personal information from MySpace users.

After MySpace booted them from the site, the pair threatened to distribute a foolproof method for stealing information unless MySpace paid them $150,000, said Sandi Gibbons, a spokeswoman for the Los Angeles County district attorney’s office.

Mondelli and Harrison were arrested Friday when they traveled to Los Angeles to allegedly collect the payoff. Instead, they were taken into custody by undercover officers from the multi-agency electronic crimes task force who posed as MySpace employees. Each was charged with two felony counts of illegal computer access and one count of sending a threatening letter for extortion and attempted extortion. They face more than four years in prison if convicted of all charges, prosecutors said.

Mondelli and Harrison entered not guilty pleas at their arraignment Tuesday. A Los Angeles Superior Court judge set bail at $35,000 and set a preliminary hearing for June 5.

MySpace.com, owned by News Corp., allows users to post photos, blogs and journals and create networks of friends.