The operators of a site that allowed users to track their visitors have been charged with trying to extort $150,000 from the service.

Shaun Harrison, 18, and Saverio Mondelli, 19, were arrested last Friday after travelling to Los Angeles to meet with undercover agents posing as MySpace employees, the LA District Attorney's office said in a statement, released Wednesday.

The meeting was part of a shakedown attempt, the DA said, and the two have now been charged with illegal computer access and extortion. If convicted, they could face more than four years in prison. MySpace had blocked Harrison and Mondelli's software earlier this year. After it did that, the defendants allegedly threatened to release new "unbreakable" code unless MySpace paid $150,000, the DA said.

Harrison and Mondelli operated the site, which offered users a way to get information on visitors to their MySpace pages. This information included visitor's email addresses, the number of visits they had paid to the MySpace page, and the address of the page they had last viewed.

MySpaceplus had claimed to be "the largest MySpace spy community anywhere," with more than 55,000 users, according to a description on the AdBrite advertising marketplace.

Harrison and Mondelli are being held on $35,000 bail each. A preliminary hearing in Los Angeles Superior Court is set for June 5.