Spencer E. Holtaway/flickr

Facebook Inc. has convinced a California appellate court to block a criminal defendant’s attempt to get nonpublic user information from the company about a key trial witness.

The Fourth District Court of Appeal found Tuesday that Lance Touchstone, who is awaiting trial on a charge of attempted murder, can’t compel Facebook to hand over private profile information and messages from the person he allegedly shot. Touchstone’s lawyers want to probe private portions of the victim’s Facebook profile for potentially exculpatory evidence after he had posted publicly about drug use, guns and his desire to rob and shoot people.

The decision from the San Diego-based appellate court held that federal internet privacy laws prohibit Facebook from handing over private user information. The decision falls in line with a 2015 decision from the First District Court of Appeal in San Francisco. The earlier decision is currently pending on appeal at the state’s high court.

Tuesday’s opinion noted prosecutors who’ve shown probable cause and obtained a warrant can get Facebook to hand over information users designated as private. But the decision also pointed out that Facebook, as a electronic communication service, is expressly prohibited from handing over private user communications by the Stored Communications Act.

The court didn’t buy Touchstone’s argument that the SCA infringed upon his constitutional rights to a fair trial and due process. Touchstone, the court pointed out, can still seek a court order at the trial court to force the victim to consent to Facebook’s production of his private communications for in-camera review.

In Tuesday’s opinion, Fourth District Justice Gilbert Nares acknowledged that his court’s decision, like the earlier case, will likely be reviewed by the California Supreme Court. “Nonetheless, we publish our thoughts agreeing with the conclusion in [the earlier case] for their potential persuasive value,” wrote Nares, joined by Justices Judith Holler and Terry O’Rourke.

Katherine I. Tesch, a deputy public defender in San Diego who represents Touchstone, said that she hadn’t spoken with her client about the decision yet but that she anticipates filing an appeal. Tesch said private information from social media sites is “constantly used as a sword against” criminal defendants. “It should be available to the defense as a shield,” she added.

Facebook is represented by James Snell and Christian Lee of Perkins Coie. Neither Snell nor Facebook representatives immediately responded to messages.

Ross Todd is bureau chief of The Recorder in San Francisco. He writes about litigation in the Bay Area and around California. Contact Ross at rtodd@alm.com. On Twitter: @Ross_Todd.