Two people have been arrested after tweets were sent to a Nottinghamshire MP calling her a "traitor" and telling her to "remember what happened to Jo Cox".
The man, 40, and woman, 33, have been released on bail, but were arrested by South Yorkshire Police in connection with a series of malicious tweets sent to five MPs, including Anna Soubry, MP for Broxtowe.
Messages were sent to newly formed Independent Group MPs including Ms Soubry, Chuka Umunna, Angela Smith and Sarah Wollaston, and Labour MP David Lammy.
The tweets were sent from an account called "Sheffield and Yorkshire direct action brexit group" which is still online.
They responded to a tweet by Ms Soubry who was referencing a petition calling for Brexit to be cancelled.
In the tweet they branded her a "traitor" and "remember what happened to Jo Cox so be careful."
Jo Cox was killed in the run-up to the 2016 EU referendum in Birstall, West Yorkshire by right-wing extremist Thomas Mair.
She was aged 41.