Mr. Moore also asked her to arrange for him to attend an asbestos conference in Brussels. She agreed to do it, unaware that his real reason for going was to see if American lawyers like her brother were funding it, filings indicate.

When Mr. Moore reported back to Mr. Bigazzi, his supervisor at K2 Intelligence, that he had not seen financial involvement by American lawyers, he said, he was told that the client next wanted him to go to Thailand, where activists were pushing for an asbestos ban. It was around then, Mr. Moore said, that he began to question what he was doing.

Mr. Moore said he learned that independent groups viewed chrysotile as being as deadly as other varieties of asbestos. He also believed that activists were right to want it banned and started to wonder whether K2 Intelligence’s client was someone other than the “U.S. investor” that had been mentioned to him.

“I don’t see the work of an arch mastermind who is unreasonably using disingenuous statistics,” he wrote to Mr. Bigazzi in late 2012, court papers show. “I see the work of campaigners who have a good argument on their side.”

Mr. Moore acknowledges that he could have simply walked away. Instead, he decided to discuss his situation with fellow Buddhists. He said he had told them that if he quit, K2 Intelligence would simply replace him. But if he stayed he might be able to do something positive by exposing the asbestos industry.

“I was told that I could absolutely do this from a Buddhist perspective providing I didn’t cause harm to anyone,” he said.

Activists suing Mr. Moore say they believe he had a more prosaic motive — money. Court papers indicate that K2 Intelligence paid him about $100,000 annually, far more than he had made since losing his television job. Whatever the case, Mr. Moore said he soon began to deceive K2 Intelligence and its client.