A football commentator said his "jaw hit the floor" when he received a threatening email that appeared to have been sent from Parliament.
House of Commons authorities are now investigating the message sent to Dan O'Hagan, who has worked for BBC, Eurosport and ESPN.
The email, sent by someone called David on Tuesday, said he was working "very, very hard" to get Mr O'Hagan's address.
The commentator said: "I was shaking, taken aback and frightened."
It was sent after Mr O'Hagan, who lives in Norfolk, criticised the radio station LBC on Twitter for employing Nigel Farage.
The email said: "You cannot be allowed to belittle, mock and intimidate working class white men, whilst peddling your bourgeoisie, privileged leftism in your highly-paid career.
"Football is not for white elites like you, it belongs to working class men of all colours.
"Send me your address now and we can discuss this further in person. It is important that we do so."
Mr O'Hagan said: "The email came through a website so it had the IP address, I ran that through a scanner and lo and behold it was from the House of Commons."
"My jaw hit the floor. Extraordinary"
'Abuse coming back'
An IP address is a unique number that every computer or device on the internet has, and includes location information.
Mr O'Hagan said he had spoken to the police about the email, but felt there was "no direct threat" against him.
"I just want the person who's done this to found and outed," he added.
Although he said the email came "immediately" after his Tweet about LBC, the 42-year-old said it could be linked to posts critical of the government.
He said: "To speak against the government on Twitter, you get, it appears from inside the House of Commons, abuse coming back at you."
A House of Commons spokesman said: "We are aware of an threatening email received by a television presenter.
"We take threats of this nature very seriously and are investigating the matter."
Norfolk Police said in a statement its inquiries into the email "found that no criminal offences had been committed and the investigation has therefore been closed".