A man Sadiq Khan's sister used to be married to was once linked to an extremist organisation.
That was the essence of the Evening Standard's "exposure" of Labour's London mayoral candidate, who is a Muslim, last month. It was one of a spate of headlines which have made tenuous ties between the Tooting MP and some unsavoury characters and organisations.
This trend culminated on Tuesday with the Tories wheeling out defence secretary Michael Fallon to brand Khan a "Labour lackey who shares platforms with extremists".
Meanwhile Khan, who has a healthy lead in the polls over Conservative candidate Zac Goldsmith, seems to be doing a good job of rising above it all.
"My worry is that by descending into this sort of desperate politics it undoes some of the great things about London," he said in an interview with Christian Today.
"I am trying to have a positive campaign. It is really important to recognise we have an opportunity to inspire, to energise and enthuse people.
"My experience is you are more likely to do that with hope rather than fear."
So is London ready for its first Muslim mayor? It would certainly send a message out to groups such as ISIS and al-Qaeda which claim the West persecutes Muslims. But a poll by YouGov for LBC seemed to suggest nearly a third of Londoners would be uncomfortable with a Muslim mayor.
Khan insists that poll was misleading and divisive. He said he was "not surprised by the generosity I have received from friends in London who have a Christian faith, a Jewish faith, Sikh, Hindu or no faith because that is the London I know".
"What is remarkable about London is we don't simply tolerate each other. We respect each other, we celebrate each other, we brake bread together, we form friendships, we join each other's families," he told Christian Today.
"What I have always sought to do both in Tooting and throughout my career in public life is to bring people together rather than divide them. I see in my own community the contribution the churches make towards food banks and towards youth work. They check up on old people and make sure the community comes together on big days, but they don't stop people coming to food banks because they are not Christian. They don't stop people using the youth facilities because they are not Christians. That is the best way to show people your faith.
"What people predicted after 7/7 [the London bombings in 2005 that killed 56 and injured over 700] was that we would divide as a city and turn on each other. In fact, the opposite has happened and people have come together and that is the best of faith."
There is a noticeable difference between how Christian and Muslim politicians in the UK are treated by the public. Lib Dem leader Tim Farron, for example, was grilled over praying about decisions and whether homosexual sex was a sin. Khan, however, has received nowhere near the same level of scrutiny about specific beliefs, and has instead been given the broad-brush smear of being associated with undesirables.
So what does Khan actually believe, and how would he describe his faith?
"I have got the values that I have because my parents instilled certain values in me. One of the things they also did was teach me Islam, in my opinion, how it really should be," he said.
"There are basic things that Muslims should do: have faith in God, pray, fast, give money to charity, perform pilgrimage. Those are the basics, if you like, but there are other things which are intrinsic to being a Muslim, like being good to your neighbour, treating others with respect, look after the elderly, get involved in your community, if you've got wealth share it, look after the environment."
But he admitted "those values don't just come from faith as in an organised religion" and said other people get the same values from "other things such as joining a political party".
"Because, I think, I know my religion, when people come up with a perverse version of my faith and use that as justification to commit acts of terror or criminality, I've got the resilience to know that is rubbish," Khan added. "The way to heaven, the way to success in this world and the hereafter, is not to carry a kalashnikov and do bad things or to kill innocent people."
So far so nuanced. He has not fallen into the same trap as Christian MP Liz Kendall who said her main motivation in life is not God but the Labour party, but neither has he followed the likes of US presidential candidates Ted Cruz and Ben Carson, who say they are running only because of their religion.
"Faith is part of who I am, but the way I would best describe it is we are multiple entities. I am of Islamic faith, I am a Londoner, I am British, I am English, I am European, I am a father, I am a husband. All of those things go towards making me who I am," Khan said.
So does he pray about political decisions?
"I am supposed to pray five times a day. Don't tell my mum but sometimes I miss them. I try to catch up. So I pray throughout the day."
About political decisions?
"About all sorts of things. The reason you pray is to bring yourself close to God. It brings you humility and submission."
Whether or not some Londoners are uneasy about a Muslim mayor, Khan himself has no doubts. He's a politician comfortable in his own skin and believes he has a lot to offer. On May 5 we'll find out whether the voters agree.
