Scotland Yard is investigating the intimidation and harassment of Stella Creasy following the “extremist” targeting of the Labour MP by anti-abortion protesters over the past week.

Metropolitan police officers said they had taken a detailed statement from Creasy, the MP for Walthamstow in north-east London, and were examining evidence to ascertain whether the campaign against the pregnant, pro-choice politician had crossed the line.

For the third time in a week, supporters of the UK branch of the Center for Bio-Ethical Reform (CBR UK), an American anti-abortion organisation, gathered in Walthamstow town centre on Saturday and became embroiled in heated exchanges with passing shoppers.

“Any criminal conduct, any harassment, any targeting, is something we are investigating and the evidence is under review at the moment, and in due course we will seek the advice of the Crown Prosecution Service,” said Supt Waheed Khan, Scotland Yard’s deputy head of hate crime. Addressing a crowded meeting organised by Creasy to discuss a fightback against the emergence of CBR UK in her constituency, Khan confirmed that “harassment and targeting” was something that “possibly goes beyond” the bounds of lawful protest.

DS Matthew Hearing, a public order officer who investigated the targeting of MP Anna Soubry by far-right supporters last year, confirmed police had taken a detailed statement from the MP. He asked the audience if they had any footage or material relating to two recent protests by CBR UK in Walthamstow as well as a billboard that was put up showing an aborted foetus and the words “Stop Stella”.

Hearing added: “I would like to collect as much evidence as possible, and anybody here who took photographs or were present during previous demonstrations, then please pass them forward, that would be greatly appreciated.”

If they were making homophobic remarks on their posters, it would not be a matter of debate that it had to be taken down Stella Creasy

The Met’s intervention followed a tumultuous week in Creasy’s constituency during which the divisive billboard was daubed with white paint before being pulled down by council officials. Creasy lodged complaints with the police, the Speaker of the Commons and the home secretary.

Creasy told Saturday’s meeting at Walthamstow Trades Hall that the actions of the anti-abortion protestors were not just an attack on her, but “collective harassment” against the women of Walthamstow.

She said: “It shows the gaps in the law that if they were showing pictures of the KKK, or making homophobic remarks on their posters, it would not be a matter of debate that it had to be taken down. We have to show that this is a form of harassment.”

She urged those present to report harassment to the council and police.

Another speaker was Dr Pam Lowe from Aston University, an expert in reproductive health, who has studied the Centre for Bio-Ethical Reform in the US and described it as promoting “shock tactics.” She said the group had previously targeted the Canadian prime minister Justin Trudeau in a similar way to Creasy over the Canadian prime minister’s pro-choice position.

Lowe added that the group’s strategy was aimed at ensuring phrases such as “baby murderer” became normalised, warning that such tactics had the potential to radicalise individuals and had incited violence in the US.

One member of the audience said she had registered a complaint with the Met last week that the anti-abortion protests constituted “gendered hate crime”, although Hearing pointed out that “to be insulted by something is not a crime”.

Another said the actions of the group were “debasing our political fabric” and described the tactics as “extremist” and “clearly gendered harassment”.