Evidence that could lead to criminal charges against an anti-abortion group targeting a prominent Labour MP has been passed by police to the criminal prosecution authorities.

The Metropolitan Police has submitted a case file to the Crown Prosecution Service and asked for advice over whether the targeting of Stella Creasy last month by supporters of the UK branch of the Center for Bio-Ethical Reform (CBR UK), an American anti-abortion organisation, constituted harassment.

The development comes as a separate group has surfaced in Creasy’s Walthamstow constituency with the stated aim of ousting her for her pro-choice stance.

The Christian Peoples Alliance (CPA), which is opposed to equal marriage and abortion, says it will focus on attempting to depose the heavily pregnant Labour candidate, who led successful Westminster efforts to decriminalise terminations in Northern Ireland.

Last month CBR UK placed graphic advertisements showing an unborn foetus with the words “Stop Stella” in several locations around Walthamstow, along with street protests.

Since then Scotland Yard revealed it was continuing to work with council officials to develop a “proportionate policing approach” to each protest. But it is the emergence of the CPA – which despite fielding 30 candidates, mainly in London, has admitted its primary ambition is targeting Creasy – that is the most recent cause of consternation to many in the constituency

Last week the group began distributing leaflets – on which the name Walthamstow was spelt incorrectly – with the prominent message: “Stop killing pre-born children.”

Creasy said: “I may be heavily pregnant but I can promise residents that won’t stop me fighting tooth and nail to protect my hometown from such toxic attempts to divide us.”

The CPA has consistently contested elections to the London Assembly but failed to gain any seats.

A crowdfunding campaign to raise a £500 deposit by last Thursday for registration as a candidate for the Walthamstow seat in the general election, and another £500 for leaflets and campaigning, had raised more than £600 by Friday evening.

A statement from the candidate said: “The CPA is needed as it’s the only party standing to uphold marriage as God intended and support family values. It is the only party committed to reducing the number of abortions with a view to eliminating them altogether in time.”