Walter Berk (whose original name was Walter Berkowitz) was an FBI informer who took the Soviet Jewry flier that I wrote and sent to it to hundreds of JDL supporters, urging them to send money to support the struggle to liberate Jews from the USSR. But the money they sent did not go to our struggle, it went into Walter Berk's pocket. He used my flier to give people the impression that they were helping me with the ongoing campaign that we were conducting against the Soviet Nazi oppressor. People sent him money thinking it was going to my activities. I had already bombed the Soviet diplomatic residence in Riverdale, New York, so people understood that we were secretly carrying on an underground campaign to put the plight of Soviet Jewry in the headlines and to hurt Soviet-American relations. Kahanists naturally wanted to help us succeed in our historic effort. Walter Berk exploited that to enrich himself, and felt that he could legally get away with it because he also contacted the FBI and agreed to become an informer against his fellow Jews.
Walter Berk used the money he raised to help buy himself a brand new car. And he refused to stop fraudulently raising money in the name of JDL.
So I placed a large firebomb under the brand new car that he bought. The firebomb completely destroyed the car. Finally, Walter Berk stopped his fundraising, and no one else in New York dared to try anything similar.