A pro-Europe Labour MP stayed away from her referendum count after death threats were made against her.
Four threats were made to the police about Pat Glass, who represents North West Durham, and who was shadow Europe minister until she was promoted on Monday to shadow education minister.
Mrs Glass did not see the threats but they were taken seriously enough by the police for her to be warned.
She said: "Police advice was that it was best to avoid being in places I was expected to be and I decided not to attend the count."
A malicious email was also sent to a member of her family, she said.
"To some extent people like me put ourselves out there but stuff directed at our families is beyond the pale," the MP said.
It was understood she would normally ignore anonymous threats as the work of "keyboard warriors" but following the killing of her parliamentary colleague Jo Cox, Mrs Glass took them seriously.
A Durham Police spokeswoman confirmed the force was investigating.
She said: "Several pieces of information have come to our attention regarding malicious communication towards Pat Glass MP.
"We have been working with Mrs Glass to progress inquiries while offering advice and support during the investigation.
"A specific threat was dealt with by officers in Consett last week, (and) working with Mrs Glass's office, appropriate action was taken and the threat negated.
"No specific instruction not to attend a count in Mrs Glass's constituency was ever discussed."
Mrs Glass campaigned for Remain and apologised after causing controversy in Derbyshire when she was recorded calling a local voter a "horrible racist".