Former FTX US President Brett Harrison has lashed out at Sam Bankman-Fried for manipulating and threatening colleagues who proposed solutions to reorganize FTX US’ management structure. 

Harrison shared his experiences with Bankman-Fried and FTX US on Dec. 14, explaining how he was hired “casually over text” in Mar. 2021 after working together at New York-based trading firm Jane Street for a few years.

But six months into Harrison’s tenure at FTX US, “cracks began to form” between the two, he said.

Despite recalling Bankman-Fried to be a “sensitive and intellectually curious person” at first, Harrison said he saw “total insecurity and intransigence” in Bankman-Fried when confronted with conflict, particularly when Harrison suggested FTX US establish separate branches for its executive, developer and legal teams.

16/49 I saw in that early conflict his total insecurity and intransigence when his decisions were questioned, his spitefulness, and the volatility of his temperament. I realized he wasn’t who I remembered.

— Brett Harrison (@BrettHarrison88) January 14, 2023

Harrison added that he “wasn’t sure what accounted for the dramatic change” in Bankman-Fried’s erratic behavior, though he suspected mental health issues may have been a “contributing factor.” 

Part of that irrational behavior Harrison describes included a series of gaslighting and manipulation tactics Bankman-Fried used against Harrison and other colleagues in their bid to clean up FTX US’ corporate mess.

Harrison also recalled his last attempt to fix FTX US’ organization issues with Bankman-Fried, claiming that he threatened to “destroy my professional reputation” if a formally apology wasn’t received:

29/49 In response, I was threatened on Sam’s behalf that I would be fired and that Sam would destroy my professional reputation. I was instructed to formally retract what I’d written and to deliver an apology to Sam that had been drafted for me.

— Brett Harrison (@BrettHarrison88) January 14, 2023

Harrison said that event “solidified” his decision to leave.

Related: FTX ex-staffer: Extravagant expenditures and cult-like worshipping of SBF

As for the fraud charges now laid against Bankman-Fried and other FTX colleagues, Harrison said he was blinded by the firm’s alleged commingling and misuse of billions of dollars of customer funds:

“I never could have guessed that underlying these kinds of issues — which I’d seen at other more mature firms in my career and believed not to be fatal to business success — was multi-billion-dollar fraud.”

“If any one of us had suspected let alone learned the truth, we would have reported them immediately,” he added.

Bankman-Fried was granted bail after posting a $250 million bond guarantee and pleading not guilty to all eight criminal charges laid against him on Jan. 3.

Harrison stepped down as FTX US President on Sept. 27 — about five weeks before FTX catastrophically collapsed — where he stated that he moved into an advisory role.