Australia has been rocked by revelations six rugby league clubs and two Australian Rules football teams are under investigation by anti-doping authorities.
Here is a timeline of key events in the unfolding controversy:
February 5 - Senior officials at Essendon Bombers, one of the country's oldest and most popular Australian Rules football clubs, hold a media conference to announce they are being probed by the Australian Sports Anti-Doping Authority (ASADA) over the legality of supplements administered to players.
A former Essendon player tells Australian television that club officials told players they were taking substances "right on the edge" of what was permitted, and had players sign forms before they took them.
February 6 - Reports emerge that Essendon players were taken away from their training base to receive injections of supplements in their stomachs.
February 7 - Officials release an explosive report, the result of a year-long probe by the country's top criminal intelligence unit, that found "widespread" use of banned performance-enhancing drugs by professional and amateur athletes.
The report says the supply is linked to organised crime and that coaches and support staff are complicit in their use.
The Australian Football League (AFL), governing body of Australian Rules, and the National Rugby League launch investigations.
February 8 - Australian bookmakers suspend bets on Essendon's season-opening match against Adelaide in March, as media reports speculate that Essendon may struggle to field a team if too many players are stood down or suspended amid the probe.
February 10 - A federal justice minister confirms multiple AFL and NRL clubs have been swept up in investigations.
The AFL confirms probes into potential banned drug use by players at Essendon and another player at a separate club.
February 11 - NRL clubs North Queensland, Penrith and Canberra confirm they have been named in investigations by anti-doping authorities.
February 12 - NRL clubs Newcastle, Manly and Cronulla confirm they have also been swept up in the probe. NRL Chief Executive David Smith says the governing body has been working with ASADA for weeks.
(Compiled by Ian Ransom; Editing by Peter Rutherford)