HARRISBURG — Pennsylvania's Supreme Court ruled Tuesday that the state police can't hide from the public its policy on how it monitors social media. Advocates for civil liberties cheered the decision. The law enforcement agency had argued that fully disclosing its policy for using software to monitor online postings may compromise public safety.

All four Democratic justices supported the majority decision, which said the lower Commonwealth Court went beyond its authority in trying to give the state police another attempt to justify keeping details of the policy a secret. Tuesday's order appears to end a six-year legal battle. A state police spokesperson said the agency is reviewing the court decision.

Andrew Christy, a lawyer with the ACLU of Pennsylvania, said the ruling “sort of puts law enforcement on the same playing field as all government agencies. If they have a legal justification to keep something secret, then they have to put forth sufficient evidence to justify that.”

People need to know what police are doing in order to decide if it's appropriate, he argued.