An attorney who filed dozens of BitTorrent copyright cases on behalf of Voltage Pictures and Millennium Films has renounced the practice, saying he was duped into participating in unethical copyright “trolling.”

James S. Davis filed suit against his former legal partner and his former clients in San Diego Superior Court in July. In the complaint, he says that he was recruited into the BitTorrent litigation by a former law school classmate, Carl Crowell, who told him he had a “good litigation business opportunity.”

Crowell, based in Salem, Ore., has filed hundreds of copyright infringement lawsuits against users of torrent sites. Crowell typically files against “John Doe” defendants who are identified solely by their IP address. He then obtains a court order forcing the internet service provider to identify the subscriber. He then demands a settlement — usually about $7,500. Though some defendants allege that someone else was using their IP address, it is often cheaper to settle than to fight the claims in court.

Davis was practicing immigration law in San Diego when Crowell asked him to help with the copyright cases in March 2015, according to the suit. Soon, Davis began filing federal suits for illegal downloads of “Dallas Buyers Club” and “The Cobbler,” both produced by Voltage Pictures, among other films.

In one of those cases in San Francisco, the defense attorney, Nicholas Ranallo, filed a motion asking the plaintiffs to post a $50,000 bond. In the motion, Ranallo blasted Davis for “copyright trolling,” and raised questions about whether Davis’ client — Dallas Buyers Club LLC — actually owned the copyright to the film. Ranallo also claimed it was impossible to know whether his client, Ryan Underwood, was actually responsible for the illegal downloads.

“The plaintiffs’ goal in these matters is not to reach a judgment on the merits, but rather to secure a dubious settlement with onerous terms that accrue primarily to the benefit of attorneys and other non-parties,” Ranallo alleged. Ranallo also cited litigation filed against Voltage by Dallas Buyers Club LLC, in which the latter stated that it had no knowledge or control over the copyright litigation being carried out in its name.

In response, Davis argued that the copyright owners were engaged in a sincere effort to combat piracy, and would only target “the worst of the worst” violators. Davis alleged that Underwood’s IP address was used to distribute “Dallas Buyers Club” over 400 times, along with 2,000 other titles.

Davis prevailed on the motion, and the case was later dismissed by mutual agreement of the parties. But in his recent lawsuit, Davis now says that in the course of preparing his response, he began asking questions and uncovering facts that undermined “his belief in the value and ethical propriety” of the copyright suits.

In a separate copyright case in San Diego, Davis says he uncovered additional troubling facts in the course of drafting a response to a judge’s threat to dismiss the case. He says he had a meeting in Santa Monica with the key figures on the plaintiff’s side, after which he “concluded that both the legal and factual basis of the Copyright Litigation campaign were unsound, and that each had been misrepresented to him.”

At that point, Davis had filed 58 copyright cases for downloads of two Voltage films (“Dallas Buyers Club,” “The Cobbler”), three Millennium films (“London Has Fallen,” “Criminal,” “Septembers of Shiraz”) and two Benaroya Pictures films (“Queen of the Desert,” “Cell”). He dismissed the cases or turned them over to other counsel and withdrew from the copyright enforcement campaign.

He then retained Ranallo — who had blasted his San Francisco case — to sue Crowell, as well as Millennium, Voltage and other entities. In the suit, Davis seeks at least $300,000 to compensate him for hours spent working on cases that were “legally and factually infirm.”

Crowell declined to comment.