A Labour party investigation into claims Carl Sargeant inappropriately touched women cannot continue after his death, a Labour AM has said.
An inquest opens on Monday and there will be an independent inquiry into how Wales' first minister handled the case.
But Swansea East AM Mike Hedges said Labour's probe could not go ahead.
"The Labour party can only do one of three things," he told BBC Radio Wales' Sunday Supplement programme.
"It can temporarily suspend somebody, reprimand them or censure them or expel them.
"None of those are actions which can be taken against Carl Sargeant now.
"So the Labour party investigation had to end because it can only be taken against Labour party members."
Mr Sargeant, the AM for Alyn and Deeside, was found dead four days after First Minister Carwyn Jones removed him from his post in the Welsh Government cabinet amid claims he had "touched or groped" a number of women.
Mr Jones announced an inquiry looking into how he handled the allegations against Mr Sargeant and his subsequent actions.
An inquest into Mr Sargeant's death is also due to be opened on Monday in Ruthin.
Cerys Furlong, chief executive of the gender equality charity Chwarae Teg, called for the allegations against Mr Sargeant to be investigated "in a slightly different way".
"I'm very mindful of the feelings and I can only imagine how those alleged victims feel at the moment," she said.
"But I think given the circumstances we have to move forward in a slightly different way now."
Wales' health secretary Vaughan Gething said he did not believe Mr Jones would resign as first minister following anger and criticism over the way he has handled Mr Sargeant's sacking as a Labour minister.
There had been speculation the first minister would stand down but Mr Gething said: "No-one's asked me anything about Carwyn's future and I'm certainly not getting into any speculation.
"I don't think there's really a chance of it happening at all."