An anti-abortion group under investigation by the police has been accused of trying to interfere in the general election by working with a religious organisation to target a prominent Labour figure.

The Christian Peoples Alliance (CPA) distributed fresh leaflets on Friday in an apparent attempt to turn the Muslim community in the London constituency of Walthamstow against the pro-choice Labour candidate Stella Creasy, who is standing for re-election.

On the leaflets were also contact details of a senior member of a separate anti-abortion organisation, the Center for Bio-Ethical Reform (CBR UK), which is under investigation by the Metropolitan police over allegations of harassment against Creasy, who is due to give birth this week.

Creasy said the development raised serious questions over undeclared electoral interference, and has sent the leaflet to the local returning officer, who is responsible for overseeing elections in constituencies. “CBR UK have never registered themselves as a political campaigning organisation but are clearly trying to influence an election,” she said. The leaflet, which claims it is “promoted on behalf of Christian Peoples Alliance”, features the handwritten contact details of senior CBR UK official Christian Hacking, the organisation’s so-called team builder. When contacted by the Observer, he strongly denied the two groups were working together in any capacity during the election and said he had been distributing the leaflet in a personal capacity. “There’s no alliance. I work three days a week for CBR UK and, on a day off, I have volunteered with the CPA [to distribute the leaflet],” he said.

My Muslim community are absolutely furious that these people have done this. Stella Creasy

In September, CBR UK placed graphic adverts showing a foetus with the words “Stop Stella” in locations around Walthamstow, and held street protests. The strategy prompted a police investigation with the Met police recently submitting evidence to prosecutors over whether the targeting of Creasy last month by CBR UK constituted harassment.

When the CPA, which on Saturday unveiled its manifesto at a Walthamstow church, was asked why CBR UK officials were apparently distributing the groups literature, its leader, Sid Cordle, also denied the two organisations were working together. “But there are individuals from CBR UK who are supporting us. Christian Hacking is supporting us, but not as CBR UK. Obviously CBR UK are quite happy for him to support us but as an organisation we are not tied to CBR UK in any shape or form.”

The offending leaflets, titled “how well do you know your MP?” list various claims about Creasy and were aimed at gaining the support of Muslim worshippers at Friday prayers at a mosque in Walthamstow.

However, members of the Muslim community alerted Creasy, who has been the subject of the campaign by anti-abortion campaigners after leading successful Westminster efforts to decriminalise teminations in Northern Ireland. Creasy said: ”My Muslim community are absolutely furious that these people have done this. They told me they were angry that people were targeting me in this way and have said this is not the kind of politics we want here.”

Cordle admitted that the CPA, which is opposed to marriage equality and abortion, is focusing its general election campaign on ousting Creasy, although it is standing about 30 candidates in total.

Creasy said that the most active group in her constituency was the CPA, with many residents receiving leaflets headlined with the phrase: ‘Stop killing pre-born children’