A dossier of messages were sent to the Metropolitan Police on Friday.
Documents, including a batch of messages from users of the Telegram app who appear to be identifiable, were sent to Scotland Yard by the Centre for Countering Digital Hate (CCDH) 金曜日に.
A 警視庁 スポークスマンは言った: “On Friday 11 2月, police received a third party report relating to allegations of malicious communications made against a serving Member of Parliament.
“An investigation is ongoing.”
No arrests have yet been made.
A Labour source said: “Of course extremists of all stripes don’t like Keir – he spent years helping to put them and their ilk in prison and keep Britain’s streets safe from them.”
The material from the CCDH, shown to The Observer, includes responses to footage of last week’s incident posted by English Defence League founder Stephen Yaxley-Lennon – better known under his pseudonym Tommy Robinson – and conspiracy theory group Resistance GB.
先週, in a slur which caused widespread criticism and calls for him to apologise, Mr Johnson accused his rival of failing to prosecute Savile while he was director of public prosecutions.
月曜日に, Sir Keir and Mr Lammy, who were walking back from the Ministry of Defence after a briefing on the situation in Ukraine, had to be escorted away from the demonstrators by police.
Although Sir Keir was head of the Crown Prosecution Service in 2009 when a decision was taken not to prosecute Savile, he had no personal involvement in the deliberations.
In an interview with The Times this week, Sir Keir said he had never been called a “paedophile protector” before.
彼が追加した: “If others want to argue that this is unconnected with precisely what the Prime Minister said one week before then let them make that case. But they’ll never persuade me that there is no link.”
Mr Johnson tweeted on Monday evening that the “behaviour directed” at the Labour leader was “absolutely disgraceful”.
Critics have said the PM’s jibe is completely unfounded and have blamed the remark for anti-Covid restriction demonstrators targeting Sir Keir outside Parliament.
Health Secretary Sajid Javid, speaking on a visit to east London on Tuesday, said the images of the opposition leader being bundled into a police car to be escorted away from protesters were “completely disgraceful”.
But the Cabinet minister, who has previously distanced himself from the PM’s Savile comments, said “the people that are to blame are the protesters themselves” rather than Mr Johnson.