The imam killed because he wasn't 'Muslim enough'
On Friday a jury at Manchester Crown Court found Mohammed Syeedy guilty of murdering a 71-year-old imam - because he wasn't Muslim enough.
This is not just a crime that shocked the Muslim community in Rochdale where Jalal Uddin was bludgeoned to death.
It's also the second in less than a year in which one Muslim has killed another for not being Muslim enough - a form of sectarianism that we haven't really noticed in the UK.
Syeedy drove the getaway car for his alleged accomplice, Mohammed Kadir, who the trial heard had wielded the hammer in a children's park. Mr Kadir fled the UK to Turkey - and is now probably in Syria.
Why Syeedy didn't follow is a mystery - he'd recently renewed his passport and both were shown in court to be supporters of the self-styled Islamic State group.
Everyone I spoke to in Rochdale said Mr Uddin was a kind man who had lived a simple life, providing religious education to the young and spiritual support to the sick, elderly and grieving.
But for Syeedy and his alleged partner, the imam was guilty of a crime against God.
Why? Because he practised a form of spiritual healing called Ruqiya which involves special spiritual amulets. The video below explains what they are:
But Syeedy didn't agree that this was spiritual - he thought it was akin to black magic.
He adhered to a violent with-us-or-against-us ideology known as "takfirism" - it's basically the belief that one has the right to declare another Muslim not to be a Muslim.
Its followers, be they supporters of the self-styled Islamic State group, al-Qaeda or another AK-47-toting outfit, believe they have the right to be the judge, jury and executioner of others, according to their interpretation of Islamic Sharia law.
So if you don't agree with their way of being a Muslim, you've abandoned the faith. And if you've abandoned the faith, the penalty is death.
This horrible crime may read like an isolated bizarre incident, but it's not.
It's the second murder in a year in the UK of someone who identifies themselves as a Muslim, by another Muslim, for purely sectarian reasons.
Shopkeeper Asad Shah was the first. He was killed in different circumstances - he belonged to a particular sect that other Muslims don't regard as being actually Islamic.
His killer was so incensed by what the shopkeeper had put online that he got in his car in Bradford, drove 200 miles to Glasgow, and stabbed him to death.
"The murder in Rochdale is a reflection of what I believe has been happening in the UK and around the world - there is a civil war within Islam right now," says Haras Rafiq of the Quilliam Foundation counter-extremism think tank.
"There are people who have been carrying out the blasphemy law and killing people who they deem not to be Muslim enough. This is something that I think we are going to see more of."