Investigator Melissa Marino, of the Middlesex District Attorney's Office describes activity on the Facebook page of Nathaniel Fujita, seated at center, near the time of the murder of Lauren Astley during Fujita's murder trial Tuesday, Feb. 26, 2013, in Middlesex Superior Court in Woburn, Mass.  Fujita is accused of killing his ex-girlfriend, Lauren Astley in July 2011.  (AP Photo/The Boston Globe, Josh Reynolds, Pool)

A prosecutor's privilege.

When prosecutors want to get a Facebook user's private posts or direct messages as evidence, they have to request it from the company through a warrant or subpoena. In most cases, Facebook will grant the information. But this sort of access is not given to criminal defendants.

A court case in California took on this issue, ultimately failing to get defendants significant new rights, but raising the question of this imbalance and its consequences. In late May, the state's Supreme Court ruled in a case involving a gang killing and Instagram threats that tech platforms generally do not have to give defendants access to private messages or content. The court said this kind of information is protected under a decades-old privacy law.

At the same time, the court dealt Silicon Valley giants a small defeat. If defendants want to use public content—any post that is not restricted to a certain audience—as evidence in a trial, companies like Facebook or Twitter could be compelled to turn it over and verify it, which they didn't have to do before.

Social media evidence can be an effective instrument in the hands of law enforcement. In Detroit, prosecutors recently built an entire case on Instagram, Facebook and YouTube posts against a deadly gang that liked to brag about its exploits on social media.

The government can't just go and retrieve any social media information it wants, but it can do so without major obstacles. For the accused trying to access social media evidence to prove their innocence, privacy protections prevail. It's a matter of one crucial right winning over another: one person's right to privacy trumps another's right to a fair trial.

The new ruling leaves this difficult conflict unresolved, while the use of social media evidence is only bound to become more prevalent in the future.

The case

In 2013, according to his own account, a 14-year-old boy shot Jaquan Rice, 19, because he feared Rice would kill him first, after Rice tagged him in violent posts on Facebook and Instagram. Prosecutors said both were members of street gangs.

Allegedly helping the 14-year-old was his older brother, Derrick Hunter, and a man named Lee Sullivan. The teenager was convicted in juvenile court, and the case of the two older men was sent to adult criminal court. The California Supreme Court ruling refers to the latter case.

Sullivan's lawyers subpoenaed Facebook and Twitter to request posts, direct messages and other information from the accounts of Rice and Renesha Lee, Sullivan's ex girlfriend. The defense wanted this data because it could be exculpatory for their client: they could show Rice's alleged threats, and that Lee, who testified against Sullivan and was the sole witness to say he was involved in the shooting, was acting out of jealousy. Facebook refused to hand over the content, claiming it was protected under the Stored Communications Act of 1986, which was intended to ban electronic communications providers from passing on user messages without their consent.

The ruling

The California Supreme Court ruled that social media companies could be forced to provide defendants public posts, the kind that anyone can access. In order to make these posts admissible in court they have to be verified, which the companies will now have to do if served with a subpoena, and if a judge determines them to in fact be "public." This makes defense attorneys' jobs easier because until now they were responsible for proving the authenticity of a public social media post they wanted to use. In California, they had to get a user's consent to do so (these rules vary state by state).

However, the court also ruled that, generally, social media companies do not have to disclose to criminal defendants private messages or posts, even if they were meant for a large group of people—like a post broadly restricted to someone's friend list on Facebook. In other words, if you at all restrict your audience, even if it's to your 1,600 friends, that's still private. The judges sent back to a lower court the matter of what posts in the case would be deemed public, and which would not.

So, what does this mean?

Because the ruling was split, each party in the case declared it a win. Sullivan's attorney, Janelle Caywood, told Courthouse News that it was a step forward for defense lawyers, who have problems getting access to public content. "This is the first blow to Facebook's stonewall over user content," she said.

Facebook told Quartz it was pleased with the decision. "The Court's opinion shows that Facebook and other companies acted properly in refusing to disclose people's private content in response to subpoenas from criminal defendants. We will continue to advocate for people's privacy," a spokesperson said.

Meanwhile, one legal expert told The Recorder that it was a win for the user, whose rights were protected.

Stephanie Lacambra, a lawyer at the advocacy organization the Electronic Frontier Foundation, told Quartz that the victory here actually lies with American prosecutors, who will continue to wield the most power over social media evidence.

Users, on the other hand, should be worried about how easy it is for law enforcement to access their data, she said.

According to Facebook's annual government requests report, the company grants law enforcement access to the information they ask for via warrants, subpoenas or court orders 86% of the time. There were more than 30,000 such requests in the last six months of 2017.

Regardless of whether a post is private or public, prosecutors can get it through a search warran. The court, Lacambra said, ignored questions of whether prosecutors should be forced to get warrants for content requested by the defense.

"There is an imbalance in access to relevant evidence between the government and the accused, which may have serious implications for the due process rights of defendants to a fair and impartial trial," she said.

Prosecutors have no obligation to look for exculpatory information. For example, if the prosecutors issue a warrant for private posts or messages from a certain period, that's all the defense lawyers can get, even if they know that information that could help them is in posts from another period.

The government is supposed to turn over exculpatory evidence to the defense if they find it, but this is an area full of abuse. Prosecutors withholding evidence is a common problem, documented by researchers.

The broader picture

As Andrew Cohen noted in the Marshall Project in January, the case boils down to "defining 'privacy' on social media, a platform that was never considered by the authors of the federal law and is by its very nature public." The laws regulating the internet are outdated, and the struggle to refresh them for today's realities goes far beyond the California Supreme Court.

A debate over how to update the 1986 Electronic Communications Privacy Act, which contains the Stored Communications Act, has been going on for years. Law enforcement officials maintain they need unfettered access to information on social media platforms in order to do their jobs, while privacy and social justice activists warn against the outsize power the government now has over our communications.

Whether the conflict over digital evidence gets resolved depends on lawmakers who, Lacambra said, would have to "think long and hard with Constitutional law academics to craft a solution to balancing defendant's due process rights with individual privacy protections." If that doesn't happen, the issue will have to come up in court once again.