This 2005 photo provided by U.S. Drug Enforcement Administration officials shows puppies rescued from a farm in Colombia destined for use by a U.S. veterinarian working for a Colombian drug trafficking ring. Veterinarian Andres Lopez Elorza used the puppies to smuggle packets of liquid heroin on commercial flights to New York City, where the heroin packets were eventually cut out of the puppies, who died in the process, according to officials. Lopez, who is Venezuelan, was arrested in 2015 in Spain in connection with the case and was extradited to the U.S. on Monday, April 30, 2018. He is scheduled to be arraigned Tuesday, May 1 in New York.

 U.S. Drug Enforcement Administration via AP

NEW YORK — A veterinarian accused of implanting liquid heroin in puppies for a Colombian drug trafficking ring has pleaded not guilty to U.S. charges.

Andres Lopez Elorza made a court appearance on Tuesday in New York City. He was arrested in Spain in 2015 and extradited to the U.S. on Monday.

Lopez Elorza stitched packets of heroin into the bellies of Labrador retrievers and other breeds then sent on commercial flights to New York City, U.S. authorities say. The packets were then cut out of the puppies, who died in the process.

Ten puppies were found during a 2005 raid on a farm in Colombia.

Lopez Elorza was ordered held without bail. His attorney had no immediate comment.

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