On a trip to Nigeria in January, Tigran Gambaryan, a compliance officer for the giant cryptocurrency exchange Binance, received an unsettling message: The company had 48 hours to make a payment of roughly $150 million in crypto.

Mr. Gambaryan, a former U.S. law enforcement agent, understood the message as a request for a bribe from someone in the Nigerian government, according to five people familiar with the matter and messages reviewed by The New York Times. He and a group of his Binance colleagues had just met with Nigerian legislators, who accused the company of tax violations and threatened to arrest its employees.

The Binance officials fled Nigeria in a panic. Later that month, Mr. Gambaryan wrote a three-page report describing the payment request and gave it to Binance’s lawyers, two people familiar with the report said. He also alerted contacts in the Nigerian government, the people said, and recounted the incident to them.

The episode was the backdrop for a second trip to Nigeria that Mr. Gambaryan took in February. On his return, he and a colleague, Nadeem Anjarwalla, were arrested by the Nigerian authorities, setting off a crisis at Binance.

Mr. Gambaryan has been held in Kuje prison in Nigeria’s capital, Abuja, for the last four weeks, after he was transferred there from a government compound on April 8. His case is the latest legal headache for Binance, which agreed to a $4.3 billion fine last year to settle charges by the U.S. government that it allowed criminal activity to flourish on its platform. In April, the company’s founder, Changpeng Zhao, was sentenced to four months in prison for his role in those violations.

The Nigerian authorities have charged both Binance and Mr. Gambaryan with tax evasion and money laundering. Binance has denied that Mr. Gambaryan had any “decision-making power” in the company.

“The message from the Nigerian government is clear,” Binance’s chief executive, Richard Teng, wrote in a blog post on Tuesday. “We must detain an innocent, mid-level employee and a former U.S. federal agent, and place him in a dangerous prison in order to control Binance.”

Zakari Mijinyawa, a spokesman for Nigeria’s national security adviser, said in a text that the Nigerian government would make its case “on the strength of the facts and evidence, in accordance with due process.”

“We are confident that Nigeria has a good case,” Mr. Mijinyawa said. “Binance equally will have every opportunity under the rule of law to make its case and see justice delivered.”

In the blog post, Mr. Teng laid out the history of Binance’s engagement with Nigeria, which has become a hot spot for the crypto industry. It has the second-highest rate of crypto adoption in the world behind India, according to Chainalysis, a data firm.

In 2023, Nigerian financial regulators issued a statement directing Binance to stop soliciting investors in Nigeria. Binance halted its advertising in the country and offered to meet with government officials, Mr. Teng said.

But tensions continued to escalate. Over recent months, Nigerian officials have argued that trading on Binance contributed to the collapse of the country’s currency, the naira. And in December, a committee of the Nigerian House of Representatives asked that Binance representatives appear for a hearing.

On Jan. 8, Mr. Gambaryan and a group of Binance employees met with those lawmakers. Soon the meeting turned contentious: The lawmakers read aloud a list of accusations against Binance, including tax violations. They also threatened to pursue an arrest warrant for Mr. Teng, the blog post said.

As the Binance employees left the meeting, Mr. Teng wrote, they were approached by “unknown persons” who suggested that they make a payment to settle the allegations. Later, a local lawyer representing Binance spoke with someone purporting to be an agent of the House committee, Mr. Teng wrote.

The purported agent demanded “a significant payment in cryptocurrency to be paid in secret within 48 hours to make these issues go away,” Mr. Teng wrote. The amount was roughly $150 million, four people familiar with the matter said.

“Our team grew increasingly concerned about their safety in Nigeria and immediately departed,” Mr. Teng wrote in his post. “We, of course, declined the payment demand via our counsel, not viewing it to be a legitimate settlement offer.”

After he left Nigeria in January, Mr. Gambaryan discussed the incident with colleagues and circulated his report describing the payment request, two people familiar with the matter said.

Later that month, Mr. Gambaryan began setting up meetings with Nigerian security and financial crimes enforcement officials. At the time, he noted that senior leaders at the financial crimes office were eager to discuss what had happened during the Jan. 8 meeting, a person familiar with the conversations said.

In a text message last month, Dele Oyewale, a spokesman for Nigeria’s financial crimes commission, declined to comment on the payment solicitation. He did not respond to a request for comment on Monday.

In his post on Tuesday, Mr. Teng wrote that Binance had received assurances that Mr. Gambaryan would be safe if he returned to Nigeria. A company adviser with deep local connections recommended that Binance officials meet with the Nigerian national security adviser’s office, Mr. Teng wrote.

Mr. Gambaryan and Mr. Anjarwalla arrived for that meeting on Feb. 26. After a couple of hours of discussion, Mr. Teng wrote, a Nigerian financial crimes official took Mr. Gambaryan aside and told him that “everything was progressing well.”

Then different Nigerian officials entered the room, demanding that Binance provide granular information about its users in Nigeria — a request the company was unwilling to meet. Mr. Gambaryan’s and Mr. Anjarwalla’s passports were confiscated, and the two men were held for three weeks in a secure compound. On March 22, their lawyers received word that criminal charges were coming.

Mr. Anjarwalla escaped the next day. He left Nigeria and has not spoken publicly since.

Mr. Gambaryan was alone in the compound. Shortly after he arrived, financial crimes officials in Nigeria had sent a note to the U.S. Embassy in Abuja, according to a copy of the message viewed by The Times.

“It is important to emphasize that Mr. Tigran is currently having a discussion with our team and the intent of his stay is purely for the purpose of constructive dialogue,” the letter said. “We assure you that the individual is participating willingly.”

Mr. Gambaryan was soon transferred to Kuje, a notorious facility where the Islamic State staged a prison break in 2022.

A trial was scheduled to begin last Thursday, but the court postponed it until May 17.

Julian E. Barnes and Glenn Thrush contributed reporting from Washington, and Sunday Isuwa from Abuja, Nigeria.