Jorge Puello, who has been a high-profile advocate for the jailed Baptists as they navigate the Haitian justice system, is in apparent violation of Dominican law for failing to register with the local bar association or obtain a license, said Jose Parra, vice president of the Dominican Lawyers Association.
Parra said his organization was still investigating the situation and might file a complaint with the Justice Department, which could pursue criminal charges.
Puello declined to comment in a brief telephone interview, saying he would be busy in court representing a U.S. firm seeking to establish a business in the Dominican Republic. He could not be located in court and did not return later phone calls.
The Web site for Puello Consulting says it has offered "full legal services" for businesses in the Dominican Republic and elsewhere since 2005. The site was taken down Friday for unknown reasons.
The New York Times reported late Thursday that authorities in El Salvador are investigating whether Puello is a man suspected of leading a trafficking ring in that country involving Central American and Caribbean women and girls.
The newspaper reported police said his picture seemed to match that of a suspected trafficker.
Puello denied any connection to trafficking in an interview with the newspaper and said he had never been to El Salvador.
Police Commissioner Howard Cotto, deputy director of investigations for the Salvadoran national police, told The Associated Press on Friday that authorities would need to compare fingerprints before they could determine if Puello was the man being investigated.
It was unclear whether Puello's lack of credentials would have any effect on the Americans detained in Haiti for allegedly trying to take 33 children out of the country without proper authorization following the country's Jan. 12 earthquake.
A Haitian judge on Thursday recommended provisional release for the Americans, but all 10. The prosecutor has said he will respond next week.
Puello said last week that nine of the 10 were about to be released, and he told reporters Wednesday the Haitian court was going to drop all charges against his clients.
Sean Lankford of Meridian, Idaho, whose wife and daughter are among those detained, said Puello provided his services for free.
"He's really shown himself to be completely trustworthy, and I truly believe he has done everything to help our people and to help us," he said in a telephone interview from Idaho.
Lankford said Puello contacted relatives of the Americans to volunteer his services.
Lawyers for another of the detained Americans, Jim Allen of Amarillo, Texas, issued a statement saying Puello does not represent or speak for their client. They appealed to U.S. Secretary of State Hillary Rodham Clinton to personally intervene in the case.
The lawyers said Allen came to Haiti on two days' notice to help the country recover from the earthquake. "No one benefits from Jim languishing in difficult conditions in a Haitian prison," the statement said.