Sources: Catalano in court Thursday

Mary Anne Catalano, a former executive assistant to Dr. Anthony Galea, is scheduled to appear Thursday before a grand jury in Buffalo hearing evidence in a federal smuggling and steroid distribution probe of the prominent Toronto-based sports doctor, according to a source close to the case.

Catalano, 32, triggered U.S. and Canadian investigations after she was stopped at the border last year and found to be transporting a bevy of medical supplies, including human growth hormone and foreign-labeled homeopathic drugs. She later told authorities the supplies were intended for Galea, who used them to treat professional athletes in the United States.

According to documents previously obtained by ESPN.com, Catalano identified 23 athletes during interviews with U.S. and Canadian authorities that she said Galea treated in the U.S. between last July 23 and when she was stopped at the border Sept. 14. Catalano said she frequently accompanied Galea on his trips across the border to assist athletes in healing from injury.

Galea is not licensed to practice medicine in the United States, though he has gained notoriety in recent years for having treated well-known athletes such as Alex Rodriguez and Tiger Woods. Galea was charged in U.S. federal court in May with smuggling and related drug offenses. Previously, Canadian authorities filed charges against him, including selling an unapproved drug [Actovegin], smuggling and conspiracy to export drugs.

Catalano, a Canadian citizen, told authorities she witnessed Galea inject a cocktail mixture containing Nutropin [growth hormone] into the injured knees of "at least seven athletes" while in the United Statess. She described the cocktail as also containing Traumeel, vitamin B-12, Lymphomyosot and Procaine.

Catalano pleaded guilty last month in Buffalo federal court to making false statements to agents when she was stopped at the border crossing, initially telling authorities the drugs and medical supplies were intended for a medical conference Galea was attending in Washington, D.C. As part of a plea deal, Catalano, who is scheduled for sentencing in October, is required to assist authorities with their investigation and appear before grand jury proceedings.

Mike Fish is an investigative reporter for ESPN.com.