But he stressed that early intervention is important and that he was part of a group who staged an intervention at the start of 2007.
“We got to a stage where we were trying to be really open with Mark but it was difficult to get a response. He just doesn’t give.
“He’s a self-made guy and didn’t necessarily want to rely on other people and give them his problems. He didn’t want to talk about any of the issues he had.
“It was difficult, really difficult.”
In 2006, Cook launched a historic review into the club’s operations and an outside consultant was hired to interview dozens of club stakeholders over 60 days.
During this time, Cook confirmed he asked Thompson a series of “direct and honest” questions, including if he was taking drugs.
“It was in the papers. People were talking about it so the question had to be asked.
“When we asked Mark questions, we had no reason to believe it wasn’t the truth.”
Thompson’s employment survived the review and he went on to coach the team to great success. But his behaviour became untenable and the issues were first raised publicly by Geelong at the end of 2010 ,when he quit the coaching job with a full year of his contract remaining and the club still in premiership mode.
At the time, Thompson said he was over coaching, but he signed a deal to work as a senior assistant coach at Essendon from 2011 and ultimately ended up filling in as senior coach at the Bombers in 2014 after James Hird was suspended.
A marriage breakdown and subsequent estrangement from his children has been said to trigger Thompson’s descent into addiction and association with criminals, with public outbursts of irrational behaviour making headlines over the years.
In June, he will face court for seven counts of drug trafficking and possession, including allegations of trafficking ice and ecstasy. Cook said he hasn’t seen Thompson for more than a year but expressed sorrow at the situation.
“I could use the words ‘disappointed’, ‘let down’. But it’s beyond that now.
“It’s about him as a person. I know the skills he had, the talent he has, the dad he was, is. And to see what’s happened is just – if there’s anything I could do for him, I’d do it.”
He said the club would have handled the situation in a more sophisticated manner if it had occurred today.
“We’ve now got qualified people in mental health, in psychology, so you rely on those people a lot more than 10-15 years ago when they were available on a casual or part time basis.”
Cook criticised the AFL for taking the “easy route” when dealing with misbehaving individuals and not standing by the organisation’s values.
“There’s compromises made for talented people,” he said, adding the AFL was often accused of prioritising broadcast and partnership deals over substance, and that needed to change.
Charlotte is a reporter for The Age.