Mr. Rousso said he was interrogated by Customs and Border Protection officers who told him that he was violating immigration law by using a tourist visa to enter the country to attend the academic conference. He said that at first they denied him entry to the United States, and told him he would be put on the next available flight to Paris.
The academics who had invited Mr. Rousso to speak in Texas became concerned when he failed to meet the driver who had been sent to collect him. They scrambled to alert immigration lawyers, the dean of the law school and Michael Young, the president of Texas A&M University.
The issue, Mr. Rousso said, appeared to be an honorarium of $2,000 that he was being paid to participate in the conference. Such payments are allowed for academics visiting the United States, but Mr. Rousso and those involved in securing his release said the customs agents appeared not to realize that at first.
“With a tourist visa, I’m not allowed to work,” Mr. Rousso said. “This is true — except for scholars.”
The agent who was questioning Mr. Rousso was “concerned that he was giving a lecture and was getting a good stipend to do that,” said Richard J. Golsan, a professor at the university who also had planned to have Mr. Rousso speak to his class last week.
Customs and Border Protection did not respond to a telephone message or email requests for comment on Sunday.
Mr. Mills, an immigration lawyer in Fort Worth, said he received a call from the dean of the law school around 9 p.m. Wednesday. “They were in a bit of a panic,” Mr. Mills said.
He set to work contacting immigration authorities at the Houston airport.
It was after 1 a.m. Thursday when Mr. Rousso was given back his passport and cellphone, taken to a public area of the airport and told he was free to go. He said he was told that the agent who originally held him was “inexperienced.”
He took a taxi to an airport hotel, where he was…