Commons Leader Andrea Leadsom has condemned a "despicable" death threat message sent to her because of her views on Brexit.
The senior minister, who campaigned for the Leave side in the European Union referendum, said the person who sent the anonymous message to her Commons office was a "coward".
The letter - similar to threats received by other Brexit supporters - claims "you have taken lives on our side" and warns "now we will take lives on yours".
Police are investigating messages sent to four MPs at the Commons.
Ms Leadsom said it was "pretty despicable whoever sent me this" adding: "We live in a democracy - death threats because you don't agree? And unsigned? Coward."
The letter, signed by "the real 48%" warns: "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."
A Metropolitan Police spokesman said: "Police are aware of threatening letters sent to four Members of Parliament at the House of Commons.
"Two of the letters were reported to police on Friday February 9, and two on Monday February 12.
"The letters are being investigated by officers from the Parliamentary Liaison and Investigation Team within the Parliamentary and Diplomatic Protection Command.
"There has been no arrest at this stage. Enquiries are ongoing."
A similar message was received by a constituent of Tory MP Zac Goldsmith earlier this month.