A New York City doctor pleaded guilty Friday to illegally writing prescriptions for human growth hormone and anabolic steroids on behalf of patients he never met.

Victor Mariani, part of a nationwide investigation into the illegal sale of steroids, said little during a brief hearing in U.S. District Court, except to acknowledge his guilt. He's convicted of 26 counts accusing him of aiding and abetting the distribution of human growth hormone and anabolic steroids and other related charges.

He could face a maximum of five years in prison and a $250,000 fine for each count. A sentencing hearing is set for June 1.

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Federal prosecutors allege Mariani was one of two doctors recruited to write fraudulent prescriptions for American Pharmaceutical Group, which advertised anabolic steroids and human growth hormone in magazines and Web sites targeted at bodybuilders.

Company owner Daniel McGlone, 54, of North Brunswick, N.J., and Ana Maria Santi, 68, who had her medical license revoked, have been charged in a separate indictment. McGlone has pleaded not guilty to the charges. A plea has not been formally entered for Santi.

Assistant U.S. Attorney Adi Goldstein said McGlone recommended drugs to customers without formal medical training, then sought prescriptions from Mariani and Santi, former medical school classmates in Buenos Aries, Argentina.

Prosecutors said Mariani never met with the patients for whom he prescribed the drugs. He occasionally requested samples of their blood, but it didn't seem to influence his decisions.

"Even if the lab work for a customer indicated a normal or high level of testosterone, a prescription for testosterone would still be written," Goldstein said.

Mariani wrote about 100 prescriptions per month between January 2005 and August 2006, earning $25 for each script. Many of those orders were filled by Orlando, Fla.-based Signature Pharmacy.

Linked to the scandal, in various reports, are baseball's Gary Matthews Jr., Jose Canseco, John Rocker, Jerry Hairston Jr., David Bell and Darren Holmes, former heavyweight champion Evander Holyfield, Pittsburgh Steelers doctor Richard Rydze, 1996 Olympic wrestling gold medalist Kurt Angle and bodybuilder Victor Martinez.

Signature Pharmacy is not charged in the Rhode Island case. But two owners, a pharmacist with the company and the business's marketing director have been indicted in Albany, N.Y., on 20 counts each of criminal diversion of prescription medications and prescriptions, criminal sale of a controlled substance and insurance fraud.

An attorney for the business, however, said Friday that Signature Pharmacy has done nothing wrong and will be cleared once the case goes to court.

"We are confident that our clients will be found not guilty," attorney Amy Tingley said at an Orlando news conference. "We intend to aggressively and vigorously defend against the baseless accusations and to restore our clients' reputations as hard working and upstanding citizens."

Robert Stanley Loomis and wife, Naomi, the owners of Signature Pharmacy, were arrested last week during a raid in which police confiscated truck loads of drugs and other evidence. Both are registered pharmacists in Florida. Robert Loomis' brother, pharmacist Kenneth Michael Loomis, and Kirk Calvert, Signature's marketing director, also were charged.

All four were freed on $30,000 bail each.

At least 13 people in three states have been indicted so far and as many as 24 could face felony charges in the Albany case, a separate investigation into illegal sales of steroids and performance-enhancing drugs.