Is somebody going to go to jail?

According to a CNET report posted Friday, police in Silicon Valley are investigating the sale of an iPhone prototype that was accidentally left in a bar by an Apple (AAPL) engineer and purchased by a gadget website for $5,000.

The purpose of the investigation, according to CNET’s source, an unnamed law-enforcement official, is to determine whether there is sufficient evidence to file criminal charges.

In California, keeping lost property when you know who the owner is — or is likely to be — is considered theft. If the property is worth more than $400, it can be classified as grand theft, a far more serious crime. Receiving stolen property is a separate crime, punishable by up to a year in prison.

According to CNET, Apple has spoken to local authorities about the incident, but it’s not clear whether the company initiated the inquiry or is planning to press charges.

The investigation, according to CNET’s source, is believed to be headed by a computer crime task force led by the Santa Clara County district attorney’s office.

Gizmodo, the site that purchased the prototype, returned it to Apple after a formal request by the company’s chief counsel, but not before dismantling the device and publishing detailed photographs and descriptions of its parts. Gawker Media’s Nick Denton, who owns Gizmodo and authorized payment, has called it “pretty much the biggest tech scoop ever.”

Neither Apple, Gizmodo, nor the Santa Clara police has returned requests for comment.

See also:

• Apple wants its secret iPhone back
• Letterman’s Top 10: Excuses for the guy who lost Apple’s top secret iPhone

[Follow Philip Elmer-DeWitt on Twitter @philiped]