In a tweet that has since been deleted, the Massachusetts State Police sent out a map plotting a series of gas explosions that resulted in at least one death and dozens of house fires north of Boston. At that time, there were 39 incidents; later that night, the number had risen to 70.

The reason the police deleted the tweet, though, was because of the bookmarks at the top of the browser in their screenshot. Take a closer look by clicking on the images in this tweet:

MA state police just inadvertently shared a screencap of all the activist pages they are monitoring in their bookmakrs when trying to share info about the fire including MA Action Against Police Brutality, Resistance Calendar and others. They deleted it. h/t @ravapic.twitter.com/hSo5zyC2hm — luke oneil (@lukeoneil47) September 14, 2018

Along with various surveillance pages, the bookmark strip has links to various left-wing activist groups, including:

1. Mass Action Against Police Brutality

2. C.O.M.B.A.T., which is the Coalition to Organize and Mobilize Boston Against Trump.

3. Resistance Calendar, which is just what it sounds like—a listing of resistance events near Boston.

4. Something called “Facebook 413,” which seems like it might be a Black Lives Matter page. (It’s less likely, but not impossible, that this link goes to a western Massachusetts activist group.)

5. Another group called “MA Activists.”

Curiously, there are no links to white supremacist or other alt-right or right-wing groups. Hmmm…

This is unfortunately less shocking than it should be. But it’s a hell of a warning: If you belong to a left-wing group in America, it doesn’t matter if you have no inclination to violence, or if the preponderance of violence happens on the other side: The police are watching.