An exclusive pet shop in the Bel-Air neighborhood has been exposed as being deceitful about the origin of puppies it sells to Hollywood celebrities by a Humane Society of the United States investigation.

Pets of Bel Air, the pet store in question, boasting with clients such as Paris Hilton and Britney Spears, was closed down Tuesday by Los Angeles officials for operating without a license, according to People.com.

The Humane Society of the United States investigated the store and found it had been operating without a license for three years.

The lack of license was not the only problem though. The Los Angeles Times reports that the agency found Pets of Bel Air sold puppies which came from unlicensed mills, for at least $1,000.

The Times reports that the Humane Society for Animals investigated pet stores and breeding operations, dubbed puppy mills, which are reputed for raising puppies in abusive and filthy conditions.

“These puppy mills apply an agricultural mind-set to the breeding of dogs,” Wayne Pacelle, president of the Humane Society of the United States, told the paper. “Often, they’re run by farmers who raise soybeans and corn, and this becomes another, more lucrative cash crop for them. It often becomes a dominant source of income because no money is spent on the care of these dogs.”

The Humane Society’s report includes video footage of overcrowded breeding operations where dogs are kept in small cages.

Pacelle added that Pets of Bel Air is not the sole pet store operating this way. “We’re not singling out Pets of Bel Air as the sole operation at fault. But they are representative.”

And a very successful operation at that, considering both Britney Spears and Paris Hilton helped business last summer; Brit acquired a yorkie while Paris took home a Chihuahua, according to People.

Pets of Bel Air has not responded to the reports yet. The Humane Society has video material showing a manager tell an employee to not let customers know the health problems of one puppy, reports the Times.