ASADA investigation unlawful: Essendon

ASADA's investigation of Essendon's 2012 supplements program was unlawful and for an improper purpose, the AFL club has told the Federal Court.

Neil Young QC, for Essendon, told the court the Australian Sports Anti-Doping Authority had overstepped its powers in its joint investigation with the AFL of the club.

"From its inception the investigation was invalid and unlawful," he said on Monday.

Mr Young said the investigation was conducted for improper purposes.