In the wake of the shooting of two police officers in New York City last weekend, local police throughout the country have stepped up surveillance of social media, taking the extraordinary step of arresting several people for allegedly making “threatening” statements.

Individuals have been arrested or charged in New York, New Jersey, Oklahoma, Massachusetts, Vermont and likely other states. Their arrests are part of a concentrated attack on the First Amendment, which is increasingly considered a barrier to national, and now city, “security.”

The shooter in New York City, Ismaiiyl Brinsley, allegedly posted to his Instagram account prior to the killings, that he was going to put “wings on pigs today.” Brinsley was clearly mentally unbalanced and had just traveled to Brooklyn after shooting and wounding his former girlfriend in Baltimore. He shot and killed himself after shooting the police.

On December 23, a man was arrested in Tinton Falls, New Jersey for posting the following to social media: “Don’t wanna get clipped while sitting in your squad car?? Don’t be a [expletives deleted] pig who’s looking to get killed … Everyone who goes out of their way to [expletive deleted] with other people should get executed in cold blood.”

On the same day, another man was arrested in Oklahoma City for posting a photograph of himself holding a semi-automatic pistol. The caption included a line of “emojis” that have been inferred by police officials to read: “bust some shots at a cop, and watch his body fall, Bang Bang.”

In New York, the Port Authority arrested a man traveling by Greyhound bus from Vermont, after a tip was received from police in Springfield, Vermont that the man had threatened on social media to engage in “suicide by cop.” The man was not found to have any weapons but did possess drugs and was arrested on that basis.

A man in Chicopee, Massachusetts faces charges that he allegedly wrote “put wings on pigs” on social media on Monday. He was not arrested but will be summoned to court for “threatening to commit a crime.”

In New York City on the same day, the NYPD arrested a young man who was a member of a “known gang” for posting an anti-police cartoon, where a gun was pointed at an officer, to one of his social media pages. A second young man, who is only 16 years old, was also arrested for posting the same cartoon.

Others charged in New York City include two men who are accused of falsely reporting threats from other people, a man who has allegedly made several “threatening” telephone calls to at least two precincts, and another man heard talking about killing police officers on his cellular phone.

Departments in other states are similarly looking for people to arrest. Ray Hunt, president of the Houston Police Officer’s Union, has stated that they are watching the internet because “the thug who killed the 2 New York Police Officers posted something on a social media website.”

One person in Texas was actively investigated by police for posting on his Facebook page, “2 down. 49,000 to go. Not an execution, just a minor insurrection and a bit of humble revenge.” Houston police issued a statement allowing that this post “constitutionally protected speech,” but added that “we remain vigilant and will review any similar items brought to our attention.”

The extent to which police departments like the NYPD have gone to surveil their precincts is also unclear. Recently, it has been discovered that they have used dragnet surveillance to map out what they believe to be “gang territories,” in order to launch large raids and collect entire groups of people. It appears that this practice has also been used in the wake of Brinsley’s shooting.

At the same time, NYPD officials and politicians have sought to implicate the wave of popular protests over police brutality in the killings, as part of an effort to criminalize opposition to the police. Patrick Lynch, president of the NYPD Patrolman’s Benevolent Association, declared: “Those that incited violence on the street, under the guise of protest, that tried to tear down what New York City police officers did every day. We tried to warn—‘it must not go on, it cannot be tolerated.’”

New York City Police Commissioner Bill Bratton, appointed by Mayor Bill de Blasio, said that the shooting was a “direct spinoff of this issue of these demonstrations,” and de Blasio himself has called for a halt to all protests.