Gennady Golovkin scoffed at the idea that Canelo Alvarez’s failed tests were the results of tainted meat. Photo: Erik Verduzco/Las Vegas Review-Journal via AP

LOS ANGELES – Nevada State Athletic Commission director Bob Bennett has filed a formal complaint against Saul “Canelo” Alvarez over the Mexican’s positive drug tests, putting his Gennady Golovkin rematch in doubt.

In the complaint filed this week, which became public on Thursday, Bennett asks the commission to impose a specific suspension on Alvarez, who had already been temporarily suspended pending a hearing.

That was originally set for April 10, but US media reported Bennett has asked that the matter be taken up during its regularly scheduled meeting on April 18.

Alvarez twice tested positive for the anabolic agent Clenbuterol in February, his camp blaming the results on tainted meat in Mexico where the drug is sometimes used to fatten cattle.

In the complaint, Bennett notes that Alvarez’s “utilisation, ingestion, and/or consumption of Clenbuterol, whether intentional or not, constitutes an anti-doping violation”.

The formal complaint heightens doubts that the much anticipated May 5 rematch between Alvarez and Golovkin will go ahead.

The Las Vegas Review Journal and ESPN reported that MGM Resorts International, owner of the T-Mobile Arena where the fight is scheduled, has begun offering refunds to ticket buyers.

Undefeated Golovkin and Alvarez fought to a split draw in a September 16 thriller that ended amid some controversy over wide discrepancies in scoring.

Golovkin last week scoffed at the idea that Alvarez’s failed tests were the results of tainted meat.

“Canelo’s cheating. They’re using these drugs, and everybody’s trying to pretend it’s not happening,” he told reporters at his mountain training camp in Big Bear, California.