Wichita ? A moving van carrying 12 illegal immigrants was stopped for minor traffic violations in Wichita, but local authorities released the occupants after immigration officials said they were too busy to handle the case, the Sedgwick County Sheriff’s Office said Friday.

“We have some real issues with immigration and illegal immigration. This has happened before,” said Sedgwick County Major Jackie Stuart. “We don’t have anything we can charge them with. … If they violated the law, we could do something, but we can’t do anything.”

It is not unusual for deputies to stop vehicles transporting groups of illegal immigrants, usually numbering 10 or 12 people, a couple of times of year, Stuart said.

The Wichita traffic stop on Thursday comes less than two weeks after the fatal crash of a small pickup truck in southwestern Kansas near Rolla carrying 19 illegal aliens. Three died and 16 others were injured.

Most of the passengers in the Rolla crash have been deported to Mexico, the U.S. Attorney’s Office said, and the driver of the truck was arrested on a federal charge of transporting illegal aliens during which death and serious injury occurred.

In the Wichita case, sheriff’s deputies found 10 illegal immigrants seated in the back of a U-Haul van and two others in the front cab. The van’s driver, an illegal immigrant living in Tennessee, had no driver’s license. He was cited with various traffic violations and let go, Stuart said.

Deputies contacted federal immigration officials to see if they were interested in holding the illegal immigrants for deportation, she said.

“I understand now they were tied up on another case in Salina and they couldn’t do it,” Stuart said. “They are stretched pretty thin too.”

Calls to area immigration regulators were referred for comment to the U.S. Immigration and Customs Enforcement office in Chicago, which did not immediately return calls.