A local Fight for $15 fast-food worker organization filed a federal lawsuit against the City of Memphis on Wednesday, accusing its police department of conducting illegal surveillance and intimidation in an attempt to stifle the workers’ protest for higher living wages.

The suit, filed by the Mid-South Organizing Committee, claims Memphis police “engaged in a pattern and practice of various intimidation tactics aimed at discouraging [workers] from engaging in protected free speech activities.”

Workers say police followed organizers home after meetings, ordered workers not to sign petitions and blacklisted organizers from City Hall. The lawsuit charges that the department’s actions violates the First Amendment to the U.S. Constitution and the Tennessee Constitution.

“MPD’s surveillance and intimidation tactics not only violate the constitutional rights of free expression and association guaranteed by both the Tennessee and United States constitutions, but they also violate the terms and conditions of a 1978 Consent Order that remains in full force and effect,” according to the complaint.

A press release announcing the lawsuit states the surveillance, harassment and intimidation began after Memphis workers participated in a nationwide day of protest on Sept. 4, 2014.

In 1978, the City of Memphis entered into a consent decree with the ACLU of West Tennessee. It placed limits on domestic surveillance by the local police force. The decree was the first of its kind and was designed to protect citizen political activities from police coercion. It also prohibits the department from harassing political groups.

“They’re trying to stop us from speaking out, but even though it’s riskier, we know we have a right to protest and we’re not going to be intimidated,” said Ashley Cathey, a Church’s Chicken worker and member of the Fight for $15 National Organizing Committee. “Our fight for $15 is changing the country and it’s the Memphis Police Department that’s going to have to change along with it.”