Swindon's ex-Deputy Mayor, who resigned over comments made about disabled children, is to be investigated by the Standards Board for England.
Dr Lister has also resigned from the Tory group
Dr Owen Lister, a retired GP, quit after using the word "guillotine" while talking about youngsters needing special care.
He maintains that his words have been taken out of context.
The independent board monitors standards in public life and could ban Mr Lister from office for five years.
Councillor Lister has admitted using the word guillotine during a Children's Overview Task Group meeting.
He says he had been referring to fears that links with children's families would be severed; and has since received abusive mail.
"The suggestion that I suggested these children should be guillotined is crazy," he said.
"My feeling is that I shall give up the council altogether."
A standards committee at the borough council voted on Monday to send the case to the national Standards Board.