When he flew to Nigeria for a business trip in late February, Tigran Gambaryan, a top compliance officer at the cryptocurrency exchange Binance, packed a small suitcase with just enough clothes for two days.
A former U.S. law enforcement agent, Mr. Gambaryan knew the trip was risky. Only a few weeks earlier, he and a group of colleagues had rushed out of Nigeria, concerned that the local authorities might detain them, five people familiar with that trip said. This time, he assured his wife, he would “get in and get out.”
A month and a half later, Mr. Gambaryan is being held at Kuje prison in the Nigerian capital of Abuja, a complex that has housed Islamic State militants and Boko Haram fighters.
After meeting with government officials in Abuja on Feb. 26, Mr. Gambaryan, 39, and a Binance colleague, Nadeem Anjarwalla, were abruptly escorted to a guesthouse controlled by Nigerian security officials, where they were held for nearly a month with no formal charges filed against them.
Then, late last month, Mr. Anjarwalla, the company’s regional manager for Africa, escaped under mysterious circumstances. Initial reports suggested he had fled Nigeria after guards permitted him to leave the guesthouse for Ramadan prayers.
Within days of the escape, the Nigerian government charged Mr. Gambaryan, Mr. Anjarwalla and Binance itself with tax evasion and money laundering — effectively accusing the company and two midlevel employees of the same crimes.
