From NBC News:
On Sunday night, New York's top terrorism cop, Deputy Commissioner for Intelligence and Counterterrorism John Miller, detailed his office's analysis and investigation into why the New York City protests have become so violent and damaging at times.
"No. 1, before the protests began," Miller said, "organizers of certain anarchist groups set out to raise bail money and people who would be responsible to be raising bail money, they set out to recruit medics and medical teams with gear to deploy in anticipation of violent interactions with police."
He added, "They prepared to commit property damage and directed people who were following them that this should be done selectively and only in wealthier areas or at high-end stores run by corporate entities."
"And they developed a complex network of bicycle scouts to move ahead of demonstrators in different directions of where police were and where police were not for purposes of being able to direct groups from the larger group to places where they could commit acts of vandalism including the torching of police vehicles and Molotov cocktails where they thought officers would not be."
Miller said that a review of 686 arrests since Thursday found that one of out of seven were from outside New York City, including Iowa, Nevada, Texas and a number of other states.
"We believe that a significant amount of people who came here from out of the area who have come here as well as the advance preparation, having advance scouts, the use of encrypted information, having resupply routes for things such as gasoline and accelerants as well as rocks and bottles, the raising of bail, the placing of medics," Miller said.
"Taken together, (this) is a strong indicator that they plan to act with disorder, property damage, violence, and violent encounters with police before the first demonstration and or before the first arrest."