Police broke into a blogger's home in search of photographs of a prototype Apple iPhone and other material, launching a felony investigation, gadget site Gizmodo and prosecutors said on Monday.

Gawker Media-owned gizmodo.com, a popular consumer gadgets site, said last week it paid $5,000 for a prototype next-generation iPhone purportedly left in a Silicon Valley bar by one of Apple's engineers.

Stephen Wagstaffe, spokesman for the San Mateo County District Attorney's office, confirmed Friday's raid and said Apple had contacted his office to report the crime. But he did not elaborate on investigation details.

The allegation was that there was a reasonable cause that a felony theft had occurred, he said. This is the beginning of the investigation.

Apple, which was not available for comment, is expected to unveil the next-generation iPhone this summer.

Trumpeted as a major scoop, Gizmodo's bloggers said they returned the device to Apple after an official request came from Cupertino, but not before taking it apart and reporting on the device's details.

But one of the blog's editors, Jason Chen, said police seized four computers and two servers, an iPad, and other devices from his home last Friday.

According to a search warrant posted on gizmodo.com, the computers may contain photographs of Apple's prototype 4G iPhone, as well as email pertaining to its purchase, call records, and research on Gray Powell, the Apple engineer who purportedly misplaced the device.

In a letter to the police also published on gizmodo.com, Gawker's Chief Operating Officer and legal counsel Gaby Darbyshire asserted the search and seizure was illegal under California law, because Chen works as a journalist for the publication, protecting him from such action.

(Reporting by Ian Sherr; Editing by Anshuman Daga)