The alleged victims, who were from Mexico and Central America, had been stripped down to their underwear in order to discourage them from trying to escape, San Marcos police told the San Antonio Express-News Friday.

"It was not great conditions, but they were not immediately life-threatening," said Police Chief Howard Williams. "It was hot. There was no air conditioning."

Police were tipped off to the situation after relatives of the immigrants began calling in to say their loved ones were being shaken down for ransom.

"We identified the mobile home yesterday evening and it was less than two hours later that we made entry into the trailer," Williams said.

Four suspects were arrested in Thursday's raid while a fifth fled on foot and was still at large Friday.