UPDATE: SAN FRANCISCO (AP) - Social media sites like Facebook and Twitter often give information about users to authorities investigating crimes. But now California's highest court has ruled the sites must also provide information to defendants in criminal cases.

The California Supreme Court says the sites can no longer ignore requests by criminal defense attorneys to provide data like screenshots, video and other information that might help clear their clients.

The information the sites must turn over would involve content that is already public.

PREVIOUS STORY: SAN FRANCISCO (AP) - The California Supreme Court will decide whether Facebook and other social media companies must turn over user content to criminal defendants.

The justices are expected to rule Thursday in a case that has pitted some of Silicon Valley's biggest companies against public defenders.

At issue are requests by a defendant charged with murder in San Francisco for videos and other content posted to Facebook and Instagram by the victim and a witness.

Lee Sullivan and a co-defendant also sought information from Twitter. The defendants say their constitutional right to a fair trial entitles them to the material to prepare their case.

Attorneys for the companies say a federal privacy law prevents the release of user content, and the defendants have other ways to get the material.

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