A Labour parliamentary candidate has accused her Liberal Democrat rival of using dirty campaigning tactics after he sent her an open letter demanding to know her view on an Islamic charity to which she has no links.

Dr Faiza Shaheen suggested that Dr Geoffrey Seeff wanted her to be publicly highlighted as a Muslim when he wrote to her about the Islamic Human Rights Commission (IHRC), an organisation she had not heard of.

The Lib Dem candidate for Chingford and Woodford Green in east London wrote that the IHRC had “been quoted saying some very unpleasant things” and criticised its support for the Iran government.

Seeff, who said he had sent a copy of the letter to the local paper, wrote that it “seems clear that the IHRC is nothing but a front for the mullahs of Tehran” and highlighted Jeremy Corbyn’s previous support for the London-based organisation, which was formed in 1997.

He wrote: “What I and the electorate want to know is how you stand on this. Can you respect and work under a person who shares the views of this unsavoury organisation or is so gullible that he has been duped by them?”

The letter, posted by Shaheen on Twitter, did not ask her view about any other issue. Shaheen, the director of the Centre for Labour and Social Studies thinktank, said Seeff’s decision to write to her about the organisation was designed to highlight her religion.

This morning I received the below from the Lib Dem Chingford and Woodford Green parliamentary candidate. pic.twitter.com/089UlZLWSM — Faiza Shaheen (@faizashaheen) October 15, 2019

“He wants me to be publicly highlighted as a Muslim,” Shaheen said. “If he had wanted me to be publicly highlighted as a Corbyn supporter, for instance, he could have written to me about anything else. I find it concerning that as one of the few Muslim women running in a marginal seat, my identity is being targeted.”

Shaheen said she had not heard of the IHRC before she received Seeff’s letter. “In the letter it says, ‘as you will know’. I run an economics thinktank. Why does he think I know about every small Islamic organisation?”

She said she had been surprised to receive such a letter from a Lib Dem candidate. “I’m kind of ready for it from the Tories,” she said. “But I was surprised to get this from the Lib Dems who champion themselves as liberals and progressives and say they don’t have a problem with racism. This demonstrates to me that they are willing to use dirty tactics in order to get votes.”

Shaheen tweeted after receiving the letter: “Has he sent a public letter to the local Conservative MP, Iain Duncan Smith, asking him if he agrees with Boris Johnson’s comments on Muslim women? Why is he singling me out on this issue?

“The local Labour party has knocked on thousands of doors in recent months and no one has ever mentioned the IHRC.”

She said she had written to the Lib Dems regarding Seeff’s letter, which she received on Tuesday.

Seeff wrote that he had a personal interest in the IHRC and the issue was “exercising the minds of a number of voters I am speaking to in the constituency”.

The Charity Commission concluded a two-year investigation into the relationship between IHRC and its trust but did not request any changes, the Times reported last week.

A Liberal Democrat spokesperson said: “We have received a complaint on this matter and will not make a further statement whilst the complaints process is ongoing.”