The FBI has looked into a Denver truck school where up to 35 Arab students paid in cash and did not seek job placement assistance afterward, Time magazine reported Sunday.

Thursday, a government official told the Associated Press that there was evidence that truck bombs could explode on U.S. soil over the weekend. This did not occur.

Some authorities fear truck bombs might be used in the future, either with traditional explosives or with hazardous or chemical cargo.

The magazine said a truck school executive tipped off the FBI that between 25 and 35 Arab men attended the school in Denver during the past two years. They did not speak English and each group used the same interpreter.

Time said the men all received driver's licenses, even though English proficiency is a requirement.