McALLEN - Federal authorities continue to investigate the parking lot sale of six Bengal tigers they believe were bound for Mexico.

On Monday, investigators interviewed workers from the Springhill Wildlife Park and Ranch, the facility from which the cubs originated.

Little is known about the park, located at 5650 Springhill Road in Calvert, Texas, about 35 miles northwest of College Station.

``This is the first time they've popped up on the radar,'' said Special Agent Alejandro Rodriguez of the U.S. Fish and Wildlife Service, which is handling the investigation.

``Agents there have never heard of these people,'' Rodriguez said. ``They've kept a low profile.''

On Sunday, police detained a group of people from the ranch who were attempting to sell the tigers to a pre-arranged buyer in the parking lot of a McAllen Wal-Mart.

Officials seized four white tiger cubs and two orange ones, aged 2 to 10 weeks.

Authorities believe the cubs were bound for Mexico, since they were being transported to a Mexican national in a Mexico-licensed vehicle, Rodriguez said. The transaction occurred around noon.

Though Springhill Wildlife does have U.S. Fish and Wildlife permits needed to sell the animals within this country, it lacks the permits needed for international sales, Rodriguez said.

On Monday, a municipal judge arraigned Michelle Ashton, who police say claimed to be the representative from Springhill Wildlife who brought the cubs to McAllen.

Ashton, 49, was charged with interference with public duties, a misdemeanor. She was arrested Sunday after rushing into the cab of a pickup containing the tigers when Monitor staff began photographing the animals.

Ashton was attempting to force the door of the vehicle closed, resulting in a brief struggle with police. Police noted the truck was on, and she could have tried to drive away if she had gotten the door shut.

Phone calls to a number associated with the ranch's Calvert address were not answered, and two people who were briefly detained by police declined to comment on the situation to The Monitor Sunday.

Meanwhile, the Bengal cubs continue to be under the care of the Gladys Porter Zoo in Brownsville and are in good condition, zoo officials said.

The tiger cubs are being held behind the scenes as they undergo tests and will likely remain under quarantine for up to 30 days so the zoo can ensure they don't pose a threat to other animals.

Dr. Amanda Guthrie, a zoo veterinarian caring for the cubs, said the animals appear to have been well taken care of.

``The breeders were known to breed a lot of tigers before,'' Guthrie said. ``Unfortunately, they know what they're doing.''

The zoo has received multiple calls from people eager to see the six cubs. Galvan said the zoo will alert the public when the cubs will be on display - which will be in the Small World Nursery - after they are done with procedures and tests.

Brownsville Herald reporter Cassandra Delgado contributed to this report.

Ryan Holeywell covers PSJA, the Mid-Valley and general assignments for The Monitor. He can be reached at (956) 683-4446.