Ms Soubry said the Prime Minister should call in Tory whips and find out what information they have on MPs.
John Wombell, 58, was jailed for eight weeks after admitting making the grossly offensive call to the Broxtowe MP's office last November.
Police are investigating an allegedly threatening tweet, in which a user urged people should "Jo Cox" MP Anna Soubry.
Anna Soubry has apologised after saying Ukip leader Nigel Farage "looks like somebody has put their finger up his bottom".
The defence minister dismissed her comment, made in the closing seconds of BBC One's Andrew Marr Show, as a "light-hearted remark".
Comedian Rory Bremner, whose impression of Nigel Farage prompted the comment, asked Ms Soubry: "Are you allowed to say that?"
Mr Farage later said he was "astonished" by the "foul-mouthed attack" and insisted the minister had "stooped to the levels of crudity that any politician would spend a lifetime apologising for".