A Charleston carriage company is dropping its defamation lawsuit against animal-rights groups who claimed the horses were being mistreated.

An attorney for Charleston Carriage Works filed the notice of dismissal Wednesday in U.S. District Court in Charleston.

The carriage company in May filed a complaint in Charleston County against the Charleston Animal Society, Charleston Carriage Horse Advocates and founder Ellen Harley. The complaint alleged that the two groups knowingly put out false information to discredit the carriage operators, including claims that a horse that had tripped had actually collapsed and died from heat exhaustion.

The case moved into federal court because the complaint also accused the groups of violating the Animal Enterprise Terrorism Act, a federal law was passed in 2006 to rein in animal activists, particularly those protesting the use of animals in medical experiments. Attorneys for the plaintiffs later filed a motion to drop that charge and move the case back into state court.

The defendants filed a motion that the case should be dropped altogether because the complaint didn’t contain enough details for the defendants to answer it.

They also argued that the carriage company needs to prove malice to sustain a claim of defamation, since Charleston Carriage Works has been part of the public debate over the treatment of horses. A public figure can claim libel only when a false statement is published with harmful intent.

Harley equates having an animal pull 17 passengers in Charleston’s heat and humidity with animal abuse. Several carriage companies recently called a press conference to ask her to take down a “Just Say Neigh” billboard on Interstate 26 calling the treatment “horse abuse.”

Harley said the dismissal confirms her claim that the suit was filed to try to keep her from speaking out.

“This lawsuit’s purpose was to harass and intimidate those who speak out for the humane treatment of the working animals,” she said.

Charleston Carriage Works didn’t immediately respond to a request for comment.