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SAN FRANCISCO — Yahoo Inc. has filed a lawsuit accusing a former employee of lifting Yahoo’s patents and confidential information, and taking them with him to his new startup.

Steven Clarke-Martin, a software engineer at Yahoo until 2007, signed an agreement granting Yahoo the rights to all inventions he developed while employed with the company, according to the breach-of-contract complaint filed in Santa Clara County Superior Court on Tuesday.

Yahoo’s attorneys, led by Morrison & Foerster partners Michael Jacobs and Richard Hung, argue the agreement encompasses several patents for systems Clarke-Martin helped invent that take context cues from media a consumer is watching and then use those cues to select relevant ads.

But four years after Clarke-Martin left Yahoo, he attempted to transfer ownership of those patents to his startup company, Media Relevance, plaintiffs contend.

Clarke-Martin declined to comment Thursday.

Media Relevance appears premised on the same idea Clarke-Martin helped develop for Yahoo’s patent. The company uses data such as words spoken in a video to select matching ads that appear on the web browser or mobile device where the video is playing, thus creating “advertising moments,” according to its website.

“Clarke-Martin and Media Relevance converted the ’596 patent for their own use, interfering with Yahoo’s rights in the ’596 patents,” the complaint states.

According to the agreement signed in 2003, Clarke-Martin also promised not to copy confidential Yahoo information without permission, and to return or destroy any such information in his possession after he left the company, according to the plaintiff’s attorneys.

But they argue that a recent forensic examination of Clarke-Martin’s Yahoo computer revealed he copied the computer’s contents to eight CDs three months before leaving the company.

Clarke-Martin never returned the discs, which contain confidential information he did not have permission to copy, according to the complaint.

Yahoo is asking the court to grant damages, declare it the rightful owner of the patents in question, and order Clarke-Martin to return all copied Yahoo information in his possession.

“Clarke-Martin performed the foregoing acts intentionally, maliciously, and oppressively, with the intent and design to damage Yahoo,” according to the complaint.

Yahoo’s Morrison & Foerster attorneys declined comment Thursday.

Contact the reporter at mkendall@alm.com.