He tested positive following an in-competition urine sample at the USA Track & Field (USATF) 2017 Masters Indoor Championships in Albuquerque.

This came before he won gold medals in the mile and 3,000m walk events at the World Masters Athletics Championships Indoor in Daegu the following month.

He will now be stripped of both of these titles and ruled out of action until after his 64th birthday in 2021.

"McPherson, 60, tested positive for the presence of an exogenous androgenic anabolic steroid and/or its metabolites, which was confirmed by carbon isotope-ratio mass spectrometry analysis," a USADA statement explained.

"The use of any exogenous anabolic agent is prohibited at all times under the USADA Protocol for Olympic and Paralympic Movement Testing, the United States Olympic Committee National Anti-Doping Policies, and the International Association of Athletics Federations Anti-Doping Rules, all of which have adopted the World Anti-Doping Code and the World Anti-Doping Agency Prohibited List.

"McPherson’s four-year period of ineligibility began on March 23, 2017, the date his provisional suspension was imposed. 

"In addition, McPherson has been disqualified from all competitive results obtained on and subsequent to February 18, 2017, the date his positive sample was collected, including forfeiture of any medals, points and prizes."

McPherson finished fifth in the 3,000m and 10,000m events at the USATF Masters Indoor Championships.

His two subsequent "victories" in Daegu in the over-60 category came in events where there were no other competitors.