Essendon chief executive Ian Robson has resigned over the AFL club’s supplements saga but the Bombers won’t say whether other officials are set to follow.

Robson announced his resignation on Thursday, saying he initially offered to resign when the saga first became public in February but the board wanted him to stay on to help the club through the tumultuous months that followed.

Robson said the internal investigation into Essendon’s governance processes by former Telstra boss Ziggy Switkowski had made it clear he was accountable for what went on last year, even though he was unaware of the details.

“As Ziggy said in his recommendations, the club CEO must be accountable for everything that happens within their organisation,” Robson told reporters.

“We all know that a lot happened at this club in 2012 that just should not have happened.

“We let down our players and their families.

“How seriously we let them down is still a matter under investigation.

“There is no excuse in not knowing and as CEO I accept that accountability.”

Essendon chairman David Evans said while the Australian Sports Anti-Doping Authority (ASADA) investigation into the club continues, the Bombers had reached a point where they felt they had enough stability to cope with a change of chief executive.

“There still are some challenges ahead of us but Ian has done an outstanding job over those three-and-a-half months in stabilising the club,” Evans said.

Robson declined to say whether others should follow his lead.

“There’ll be now matters for change that David and the board and the incoming CEO can make with the benefit of fresh air,” he said.

Evans wouldn’t comment on potential further staff changes, but suggested the findings of the ASADA investigation would be pivotal.

“There will be some change as a result of not only Ziggy’s report but the investigation which hopefully is nearing its completion,” he said.

“We’re now starting to at least sight the end.”

He said ASADA had nearly finished interviewing Essendon players.

The Bombers expect to make an announcement on Friday about a caretaker chief executive.

Robson hopes to find another job in sports administration and said he had learnt from his failings.

“I am now going to commit myself to becoming a better sports administrator,” he said.

“Working through this period has taught me a lot and the passion I have to work in this industry is undiminished.”