HOUSTON (AP) _ A federal probe of a fatal bus crash earlier this year near Victoria has prompted Texas transportation officials to investigate why that bus and 22 others were registered through a Dallas bus company shut down this summer, according to a newspaper report.

The Houston Chronicle used a private database to find more than 30 buses located at a Dallas bus company, Green River Buses. One of the buses was a 2005 Volvo bus involved in a Jan. 2 wreck near Victoria, 125 miles southwest of Houston, that killed one man and injured several people.

Some of the buses found appeared to be owned by Green River, but others were owned by as many as seven other companies based elsewhere, including Houston and Fort Worth.

The Federal Motor Carrier Safety Administration, which is investigating the Victoria crash, ordered Green River Buses of Dallas to shut down in August. The company also had been ordered to do so in April.

The bus in the Texas wreck was owned by Capricorn Bus Lines Inc. of Houston and leased to International Charter Services Inc. The NTSB uncovered that the bus was registered in Dallas County, not Harris County.

Further investigation by the NTSB revealed that the owner of the Mexican-made bus went to great lengths through Green River to register the bus first in California, which does not require a title for a license plate, and then trade the California plate for a Texas one.

Texas vehicles are supposed to be registered in the county where the owner is based.

The license plate registrations of at least 23 buses tied to Green River Buses were turned over this week to the Texas Department of Public Safety for further investigation, Texas Department of Transportation spokeswoman Kim Sue Lia Perkes said

At least 17 of those buses are Mexican-made, prompting questions as to whether they were built to U.S. safety standards and whether they entered this country legally.

"TxDOT is vigilant about how we go about registering motorcoaches that come into our borders from Mexico," Perkes said. "We do everything we can to ensure the motorcoaches on Texas' highways and roads are safe."

Miguel Luna, owner of Fort Worth-based Autobuses Aztecas, said he authorized Green River Buses to help him register two or three of his company's buses.

"What happened is, I didn't know how to register a bus, how to handle the paperwork," said Luna, who did not have an address for his firm. He also said he bought the bus in Mexico.

The problem of Mexican-made buses illegally coming into the United States is widespread, said Brigham McCown, former general counsel of the Federal Motor Carrier Safety Administration.

"My understanding is, there are more than (those in Texas) that are running around. They just haven't found them all yet," he said. "I've been told by senior (Department of Transportation) officials there are quite a few of these buses around the country, and they are actively looking for them."