More than 100 former federal prosecutors called on US Secretary of State Antony Blinken to facilitate the release of the top manager of the largest crypto exchange Binance, Tigran Gambaryan, from a Nigerian prison.

A joint letter sent to Antony Blinken states that Binance’s head of financial crime enforcement, Tigran Gambaryan, has been detained by Nigerian authorities on false charges. He is charged with money laundering through cryptocurrencies and tax evasion.

Former federal prosecutor Kathryn Haun believes Gambaryan should not be punished for these charges because he is an ordinary mid-level employee at Binance and can only serve as a deputy. Hon noted that Gambaryan has been kept in terrible conditions for about three months, without proper medical care, despite the deterioration of his health. Gambaryan does not have the opportunity to seek legal assistance.

Kuje Prison, where Gambarian is currently imprisoned, houses some of the worst criminals in Nigeria’s history. Former prosecutors asked to take into account that Gambaryan had previously helped in the investigation of high-profile cases related to child pornography, national security, terrorist financing and other serious crimes.

On Wednesday, House Foreign Relations Committee Chairman Michael McCaul, a Republican, and 15 other members of Congress wrote to President Joe Biden, calling on his administration to take immediate action to free Gambaryan.

Gambarian and Binance’s other regional manager for Africa, Nadeem Anjarwalla, were detained upon arriving in Nigeria on February 26. Anjarwalla escaped from custody in March and was later tracked down in Kenya. In May, the Federal High Court in Abuja refused to grant Gambaryan bail out of fear that he too might abscond and evade justice.