DETROIT (AP) - Thousands of people may have exploited a recently closed loophole in Michigan regulations to fraudulently obtain state driver's licenses, a federal investigator says.

Federal agents are investigating what they say are criminal rings that helped people get licenses without proof of residency in Michigan.

Last month, secretary of state offices began requiring adults applying for their first driver's license or personal identification card to provide documentation showing they live in the state...

In July, the Portuguese language Brazilian Voice newspaper in Newark, N.J., ran an ad offering Michigan driver's licenses for $1,000, and similar ads appeared in other foreign-language publications...

There was also a Brazilian connection to fraudulently obtained Connectictt licenses.