OKLAHOMA CITY (AP) -- Authorities confiscated a charter bus carrying more than a dozen people after it was stopped at a truck stop near Interstate 40 in west Oklahoma City on Wednesday.
Local authorities were asked to assist a federal task force in intercepting the bus, Oklahoma City police Sgt. Paco Balderrama said.
"This deals with a federal grand jury. It's an ongoing, undercover investigation," Balderrama said.
Television footage showed several individuals with their hands secured behind their backs with plastic ties, and police dogs sniffing the luggage compartment of the bus. Balderrama said there were about 18 people on the bus, which was taken to a separate location so authorities could search it further. Other evidence was also seized.
Balderrama said Oklahoma City police did not take anyone into custody. A spokesman said Oklahoma County Sheriff's Office was not involved.
Special Agent Terri K. Wyatt with the Drug Enforcement Administration said Treasury Department and Wisconsin authorities were in charge of the investigation.
A Treasury Department spokeswoman did not immediately return a message left with the agency's 24-hour media hotline.
Trooper Betsy Randolph said the Oklahoma Highway Patrol was initially told the bus was from Mexico, but that information was later refuted. Randolph said she did not know where the bus came from or where it was headed.