Milwaukee police officers Robert Parks and Adam Maritato are among 20 plaintiffs suing gun maker Sig Sauer over a gun the officers and others claim is defective and dangerous.The weapons are believed to have fired multiple times without the trigger being pulled, causing several injuries to members of law enforcement for years, according to newly filed documents in federal court.WISN 12 News spoke with one of the attorneys representing the officers. Robert Zimmerman, with Saltz Mongeluzzi & Bendesky P.C. in Philadelphia, said he gets calls weekly about new incidents involving P320s misfiring."This gun is supposed to protect those who protect and serve us and ultimately they are in the line of fire," Zimmerman told WISN 12 News. In July 2020, while putting a handcuffed man into a squad car, Parks holstered Sig Sauer P320 fired and hit Maritato in the leg, WISN 12 News has previously reported."We've seen many instances where the gun has fired where the hand is not and cannot be on or near the trigger," Zimmerman said.The incident was the first of three cases of what the Milwaukee Police Department described as "unexplained discharges" of the P320. Department officials adopted the term because its own investigators and senior leadership, according to a source who has direct knowledge of the department's internal investigations into the three incidents, have not been able to either recreate a scenario where the gun could fire on its own or explain why the incidents happened."While the full extent of the physical damage to Maritato's leg is not yet known, he has had and it is likely that he will have trouble running, sitting, or standing as he had before the incident, and will likely never be able to return to his pre-incident form as a result of diminished physical capacity," the lawsuit claims.WISN 12 News also spoke with Milwaukee Police Association President Andrew Wagner Thursday."They still deal with that, that shock every day and obviously deals with the guilt of his gun going off and shooting his partner," Wagner said.After three accidental shootings within Milwaukee Police since 2020, The union fought to get MPD's P-320 firearm replaced and starting next year the department will swap out the weapon."I won't say a ticking time bomb, but it's something that is just going to keep repeating itself. We believe, unless something changes," Wagner told 12 News.In addition to Parks and Maritato, plaintiffs include state and federal officers, as well as what lawyers described as experienced military veterans and civilians who were injured in similar cases. While there are other lawsuits targeting the gun maker over the P320, the lawsuit filed on Wednesday is described by lawyers as unprecedented given the number of plaintiffs joining in the single suit."These men and women were highly trained officers, veterans, and responsible and safety-conscious gun users who put their trust in Sig Sauer, unaware that the gun they used to serve was a danger to themselves and anyone around them. We intend to prove that the Sig Sauer P320 is without question the most dangerous pistol on the market in the United States," Zimmerman said in a statement. Sig Sauer, in response to previous lawsuits, denied knowingly selling a defective product to law enforcement agencies across the country and around the world.A WISN 12 News investigation in October 2021 first exposed the concern over the gun within the Milwaukee Police Department. Sig Sauer has never responded to 12 News requests for comment.This is a developing story.