At the “Davos in the Desert” investor conference in Saudi Arabia three weeks before FTX went bankrupt, Sam Bankman-Fried, the founder of the major cryptocurrency exchange, badmouthed rival ChangPeng Zhao, CEO of Binance, the New York Post reports.

Word of Bankman-Fried’s (nicknamed SBF in crypto circles) insolence got back to Zhao (whose own moniker is CZ), who was one of SBF’s early backers and is highly respected in the technology industry.

Zhao was instantly enraged, according to a crypto insider, who said of SBF’s indiscretion, “He pulled the pin out of the grenade on this trip.”

SBF and CZ have traded not-so-thinly-veiled jabs at each other over the past year, allegedly beginning when FTX attorneys claimed Binance thwarted their efforts to set up a subsidiary.

FTX’s implosion, according to Coindesk, was set off earlier this month when CZ sold a large holding of FTT, the cryptocurrency token for FTX.

“It’s not a coincidence he (SBF) goes to the Middle East and comes back bankrupt,” the cryptocurrency source said. “The trip created the unraveling of the fraud. There’s a direct causation between that marketing junket and Bankman-Fried’s downfall.”

In an interview with The New York Times on Monday, Bankman-Fried admitted he had spoken poorly of Zhao to U.S. officials in Washington and that attacking his rival “was not a good strategic move.”

Spokespeople for FTX and Binance did not respond to a NYP request for comment.