Elon Musk hired a private investigator to dig up dirt on a British cave diver he baselessly accused of being a “pedo guy,” Buzzfeed News reports. The bad blood between the two men began after Musk offered to send a submarine to help rescue a boys soccer team trapped inside a Thai cave for nine days, and Vernon Unsworth, an experienced cave diver who went to Thailand to help with the rescue operation, was quoted by CNN as saying the submarine “had absolutely no chance of working.” Musk shot back on Twitter, writing: “We will make one (video) of the mini-sub/pod going all the way to Cave 5 no problem. Sorry pedo guy, you really did ask for it.” Unsworth then filed a defamation lawsuit against Musk, alleging that the tech CEO slandered him by calling him a “pedo guy” and later a “child rapist.”

Musk appears to have needed proof to back up his accusations against Unsworth, so he hired a self-proclaimed private investigator who had emailed him offering to “dig deep,” Buzzfeed reports. But the man Musk hired, James Howard-Higgins, reportedly turned out to be a convicted felon and scammer. Howard-Higgins served 18 months of a three-year sentence in October 2016 for stealing about $525,000 from his company, according to court documents cited in the report.