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.

Apple announced on Friday that the Wi-Fi versions of its long-awaited iPad will arrive April 3 in stores in the United States. The models that can tap into AT&T’s 3G wireless data network will be available in late April.

Customers can pre-order the iPad on Apple’s Web site beginning next Friday.

Apple’s tablet computer is expected to ship with 12 new applications designed specifically for the device, and it will run almost all of the more than 150,000 applications available for the iPhone and iPod Touch.

Apple has been aiming the iPad squarely at e-book readers like Amazon.com’s Kindle. And in its news release Friday, Apple said that an updated version of its iBooks app that will include Apple’s iBookstore will be available as a free download on April 3 in the United States, with additional countries to be added later.

The company has been aggressively recruiting personnel for the new iBookstore, listing a variety of iBook-related job openings on its corporate job board — including “Manager, iBooks Asia Pacific & Canada,” “Independent Publisher Acct. Mgr., iBookstore” and a “Merchandising Manager, iBookstore.”

Apple said that pricing for the device will be the same as it initially announced in January:

iPad will be available in Wi-Fi models on April 3 in the United States for a suggested retail price of $499 for 16GB, $599 for 32GB, $699 for 64GB. The Wi-Fi + 3G models will be available in late April for a suggested retail price of $629 for 16GB, $729 for 32GB and $829 for 64GB. iPad will be sold in the United States through the Apple Store (www.apple.com), Apple’s retail stores and select Apple Authorized Resellers.

Apple said the iPad will be available in both Wi-Fi and 3G models in late April in Australia, Canada, France, Germany, Italy, Japan, Spain, Switzerland and the United Kingdom, with more countries added later this year.