The United States and Nigeria often collaborate. But the arrest of an American worker strained their diplomatic relations.
After eight months in custody in Nigeria, an American working for the cryptocurrency firm Binance is coming home, ailing but alive, in a case that had strained U.S. ties with one of Africa’s most influential countries.
Tigran Gambaryan, a compliance officer for Binance, had been held on money-laundering charges as part of a sweeping Nigerian government case against the company.
On Thursday, a plane equipped with medical equipment departed Abuja, Nigeria’s capital, to bring him back to the United States. During his detention, Mr. Gambaryan had contracted malaria and double pneumonia, and he has a herniated disk.
His release came after months of diplomatic pressure by the United States and in return for American promises of an improved partnership with Nigeria, including on cybercrime investigations.
The detention of the American came as Nigerian frustration over Binance and other companies was rising, and as officials there sought more help in cracking down on cryptocurrencies for their country’s economic crisis.
Mr. Gambaryan had arrived in Nigeria just days before he was arrested in February. He was initially held in a government-owned guesthouse but was transferred to the notorious Kuje prison in April.