The authorities in San Mateo County in California are considering whether to file criminal charges in connection with the sale of a missing next-generation iPhone belonging to Apple.

The San Mateo district attorney could act by early next week, according to people involved in the investigation. The office has the option of filing felony charges.

According to California law, if property doesn’t exceed $950, a case will be classified as a misdemeanor, but since the technology blog Gizmodo paid $5,000 for the device, a felony charge would be possible.

On Monday photographs and video of a possible next-generation iPhone, which is expected to be announced in June,appeared on Gizmodo.com. After some speculation about the authenticity of the iPhone, Apple’s legal counsel sent Gizmodo a letter asking that the device be returned. The letter stated: “It has come to our attention that GIZMODO is currently in possession of a device that belongs to Apple.”

Brian Lam, Gizmodo’s editor, said the organization had returned the device and that Gizmodo “didn’t know this was stolen when we bought it.”

In a New York Times article on Tuesday, Nick Denton, chief executive of Gawker Media, which owns Gizmodo, explained over instant message that Gizmodo paid $5,000 for the phone.

According to people familiar with the investigation,  who would not speak on the record because of the potential legal case, charges would most likely be filed against the person or people who sold the prototype iPhone, and possibly the buyer.

Gaby Darbyshire, Gawker’s chief operating officer, said in an e-mail message Friday that the organization had not been contacted by law enforcement officials, and declined to speak further on any legal aspects. Apple also declined to comment.

Stephen Wagstaffe, San Mateo County’s chief deputy district attorney, explained that “if there is any case that arises out of our office at this point the police have not submitted for prosecution.” He added: “We certainly know about what happened here in Redwood City” regarding the missing iPhone, “and we are the jurisdiction for any legal prosecutions” that could come out of the episode.

California law prohibits the sale of stolen goods and states that a person who uses someone else’s lost property without permission may be guilty of theft.

Mr. Wagstaffe said in cases like this it might not necessarily be a matter of lost versus stolen. In some instances of missing property, he said, “we call it misappropriation of lost property; it’s a crime but it’s not theft.” He added that “knowledge is a very important factor in a theft case.”

CNet reported on Friday that a task force, the Rapid Enforcement Allied Computer Team, had been investigating the case.

According to its Web site, the group is a computer task force made up of “17 local, state, and federal agencies, with the Santa Clara County District Attorney’s Office designated as the lead agency.” The purpose of the organization is to “arrest and prosecute a wide range of criminal offenders” related to high-tech business.

Opera Software on Tuesday announced that it is submitting its Opera Mini Web browser to Apple for use on the iPhone.

The Norwegian company boasts that Opera is the most-used browser on mobile devices; it offers a version of the software for Windows Mobile phones, Google Android and the Nintendo DS game system.

The Opera team said they are confident their new browser will be approved for the iPhone, but the final say is still up to the gatekeepers at Apple who are known to block applications in the iTunes store for any number of random reasons.

Last week I had a chance to sit down with Opera’s co-founder, Jon Stephenson von Tetzchner, to see an early version of the new iPhone software. The new browser loaded pages extremely quickly, as you can see in the video below, and manages to integrate some unique features that are currently available in its desktop browser. Some of the highlights include unlimited tabbed browsing and the ability to search the content of a Web page — an important feature that is currently unavailable on the Safari mobile browser made by Apple.

The software was missing an important feature on the iPhone: the ability to resize a page by pinching a page with both fingers.  Mr. Tetzchner said this could be added to the software with a later update.

The Opera browser loads Web pages rapidly by using a technology called server-side rendering, which compresses most aspects of a Web site on a server, sometimes reducing the load time of 90 percent of a Web page, before sending the data along to a phone’s browser.

Mr. Tetzchner pitched the new Opera browser as a way to reduce roaming charges when traveling.

Opera Software says its mission is to make a browser for any computer and mobile phone.