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St. Louis Police Now Encrypting Radio Traffic After Protesters Listened In

Protest on 10-9-14, probably along Flora place
Joseph Leahy/St. Louis Public Radio

The St. Louis Metropolitan Police Department has begun encrypting its radio transmissions after a night of unrest in south St. Louis.  

The department has had the ability to encrypt its scanners for several years, said Chief Sam Dotson in an interview with St. Louis Public Radio. But he had never felt it was appropriate to do so until after Thursday night, when protesters listening to the department's radio traffic on cell phone apps began adapting in real time to the tactical information being relayed. 

"We were seeing tweets that said, are you listening to the city police scanner app? If you've got red on, take it off, because they're looking for someone wearing red," Dotson said. "Don't go down this street, because the police are there."

Doston said he was concerned about his officers' safety. It became a public safety concern, he said, when protesters began putting the addresses of 911 callers on social media as well.

"People have to feel comfortable that if they want, their identity will be protected when they call 911," he said. "The fact that that information was now being shared in social media, that was really the decision for public safety, that we needed to encrypt our radios."

Dotson said he'll re-evaluate the decision to encrypt transmissions in about a month.

The chief also said he'll be evaluating on a case-by-case basis when to allow protesters to march in the streets of the city.

"Certainly, an interstate is different than a side street, is different than a major arterial," he said. "So we have to look at it on a case by case basis – weather, number of people, time of day, how long the duration."

Officers used pepper spray Thursday night to disburse a group of protesters who refused to clear South Grand Boulevard near Arsenal Street. Dotson said that while the department has work-arounds, traffic needed to be allowed to move to make it easier to get to Saint Louis University and Cardinal Glennon hospitals.

Follow Rachel Lippmann on Twitter: @rlippmann

Rachel is the justice correspondent at St. Louis Public Radio.