Police accidentally revealed their spying on progressives -- then tried to delete the evidence

The Massachusetts State Police accidentally revealed surveillance of progressive political groups in a social media post on gas explosions in Lawrence, North Andover and Andover, WBUR reports.

The police posted an image of 39 gas explosion locations. But the screengrab of the police computer included the browser's bookmarks bar.

The post showed police had booked pages for Massachusetts Action Against Police Brutality (MAAPB), the Coalition to Organize and Mobilize Boston Against Trump (COMBAT), and other activists organizations.

Police were also monitoring a "Resistance Calendar" of anti-Trump protests.

Kade Crockford, director of the Technology for Liberty program at the Massachusetts branch of the ACLU, slammed the revelation.

"I wasn't surprised — but I was appalled," Crockford told WBUR. "American law enforcement has, for a very long time, targeted dissidents. A lot of people like to believe those tactics ended. But that's not true — and actually, after 9/11, they've seen a substantial resurgence."

Police, in a statement, said such monitoring is "a common – and common-sense – function of any police department."

COMBAT, the Coalition to Organize and Mobilize Boston Against Trump, also issued a statement in response.

"The fact that state police, who are funded by our tax dollars, are spending time monitoring groups on Facebook who oppose racist, sexist, homophobic and transphobic violence instead of those groups who perpetuate such violence is abhorrent and should be examined with scrutiny," COMBAT wrote.

The group said police resources would be better spent investigating supporters President Trump in the so-called Alt-Right.

"COMBAT has actively resisted demonstrations held by members of the so-called 'alt-right', who have appeared in public bearing weapons and clad in racist symbols and flags. We question why time is being spent monitoring a group such as COMBAT, who actively condemns these violent ideologies, rather than on these groups who appear in public with weapons," they wondered.

"We are deeply disconcerted about police surveillance of the left in Boston, as this exists within the historical context of state surveillance and repression of organizations fighting for social justice," they added.

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Screengrab of since deleted @MassStatePolice Twitter post via WBUR[/caption]