SAN FRANCISCO (MarketWatch) -- Google Inc. and News Corp. could be heading for a legal showdown after News Corp.'s Twentieth Century Fox served Google's YouTube online video site with a subpoena demanding the identity of a person who uploaded pirated episodes of the Fox televsion network shows "24" and "The Simpsons."

A subpoena filed with the U.S. District Court for the Northern District of California demanded that YouTube give up the names of the person or persons who posted the season premiere of "24" online prior to its debut on Fox, as well as 12 episodes from "The Simpsons."

The subpoena was filed by Jane Sunderland, vice president of content production for News Corp.'s NWS, -3.57% Twentieth Century Fox.

In a statement, YouTube said it was cooperating with Fox's request.

"Fox alerted us to the videos and per our policies on copyrighted material, we removed them promptly," said the YouTube statement. "Subsequently, we received a subpoena and will comply with valid U.S. legal process. As a matter of policy we do not publicly discuss legal matters."

As the popularity of YouTube has grown, the site has come under growing scrutiny over the matter of pirated and copyrighted video posted online without proper permission from media companies.

YouTube has a history of cooperation with a similar request in the past. Last year, YouTube turned over to Viacom Inc.'s VIA, -9.09% Paramount Pictures details of about a person who uploaded content from the studio's move "Twin Towers" to the YouTube site. See full story.

YouTube has also made deals with companies such as CBS Corp. CBS, -4.76% and NBC Universal GE, -1.21% in order to avoid lawsuits over material posted to its site.

News Corp. spotted the episodes on Google's YouTube Web site on Jan. 8, more than a week before "24's" two-night, four-hour season opener was scheduled to air on Fox TV. A YouTube spokeswoman said the videos were removed that day.

Ten days later, the situation escalated dramatically. On Jan. 18, News Corp. asked that a U.S. District Court judge command YouTube, which is owned by Google Inc. GOOG, +0.32% to take down the videos, and turn over information to identify the YouTube subscriber.

News Corp. is seeking the YouTube subscriber's name, home address, telephone number, email address and information about the Internet connection used to upload the videos, according to the filings. The subscriber goes by the screen name ECOtotal, News Corp. alleges.

The company wants to "stop the infringing activity," and the information "will only be used for the purpose of protecting (our) rights," according to a letter sent to the court signed by Karen Thorland, of the law firm Loeb & Loeb LLP in Los Angeles.

Michael Graham, an intellectual property lawyer and partner with Chicago-based law firm Marshall Gerstein & Borun, said it should come as no surprise that Fox would use legal means to get the content removed from the YouTube site. But, Graham said that taking down a video and giving up the identity of the person who posted that video represent entirely different legal issues.

Graham said that under the notice and takedown provision of the Digital Millennium Copyright Act, YouTube needed to remove the videos in question as soon as it received a notice of infringement from Fox. However, without a subpoena, YouTube wasn't required to divulge the identities of the video posters.

And even with a subpoena, Graham said that finding out the name of the poster isn't that simple.

"Even with the information and server tracking which they can provide to Fox, it may be difficult or impossible to track down posters of illegal videos if those individuals use any of the various redirect or anonymizer programs which are available," Graham said. "In these cases, some solution needs to be arrived at which prevents users hiding behind such systems from repeat postings."