Trainer Sam Kavanagh is under investigation after Midsummer Sun returned  illegal levels of cobalt and caffeine after winning the Gosford Cup in January.Trainer Sam Kavanagh is under investigation after Midsummer Sun returned illegal levels of cobalt and caffeine after winning the Gosford Cup in January. Photo: Paul Harris

Racing NSW stewards heard allegations of cobalt supply, cash payments and standover tactics by key members of Flemington Equine Clinic in an explosive first day of Sam Kavanagh’s case on Tuesday.

Stewards from Racing NSW and Racing Victoria have been running parallel investigations, with Kavanagh’s father Mark and Danny O’Brien mentioned often throughout evidence on Tuesday.