Cabinet Minister Andrea Leadsom has called out the "coward" behind a death threat apparently sent to her by anti-Brexit activists.
Posting an image of the letter to Twitter, the Leader of the House of Commons, the latest MP to receive such a threat, said whoever sent the message was "pretty despicable".
The letter, which purports to be from "THE REAL 48 PER CENT", reads: "If you attempt to take away part of someone’s identity, there are consequences.
"We have watched as you have led us to the edge of the abyss. We will watch no longer. You have taken lives on our side. Now we will take lives on yours.
"We are coming for you."
Ms Leadsom has been an ardent supporter of Brexit and was a high-profile campaigner during the referendum, appearing on a national television debate.
She is not alone in receiving death threats over her Brexit views. Several Vote Leave donors are also thought to have received similar letters.
Tory MP Zac Goldsmith also said last week that one of his Richmond Park constituents had received a similar letter.
The Metropolitan Police confirmed they were aware of four threatening letters sent to MPs and that investigations were under way.
Picking up on Ms Leadsom's tweet, Remainer MP Anna Soubry - who last week called for the prime minister to "sling out" hardline Tory Brexiteers - said whoever was sending the threats was "committing a criminal offence [and] undermining free speech".
Ms Leadsom is understood to be one of the MPs to have referred the threat to the police.
"The letters are being investigated by officers from the Parliamentary Liaison and Investigation Team within the Parliamentary and Diplomatic Protection Command," the police said.