The American Civil Liberties Union on Tuesday blasted former U.S. Attorney Zachary Fardon for what it characterized as a “blindsided attack” on a 2015 agreement curtailing the Chicago Police Department’s use of stop-and-frisk measures.

In an open letter released to the media after he left office Monday, Fardon said the ACLU’s settlement had “swung the pendulum hard” away from pro-active law enforcement by “telling cops if you go talk to those kids on the corner, you’re going to have to take 40 minutes to fill out a form, and you’re going to have to give them a receipt with your badge number on it.”

Fardon said the new procedures for street stops, as Chicago police call them, were a key reason for the spike in violence that began in early 2016 and had a chilling effect on many police officers who “no longer wanted to wear the risk of stopping suspects.”

In response Tuesday, Karen Sheley, the police practices director for the ACLU of Illinois, said Fardon’s opinions were out of line with the Justice Department’s own investigation that found widespread constitutional abuses of citizens, particularly in low-income minority neighborhoods where the majority of street stops occur.