British counter-terrorism police are investigating the murder of a Syrian preacher described as a prominent critic of President Bashar al-Assad, London police said on Wednesday, according to AFP.
Abdul Hadi Arwani, 48, was found dead in his car with gunshots to the chest in north-west London on Tuesday.
The Counter Terrorism Command or SO15, a specialist branch of the London's Metropolitan Police Service, is taking charge of the investigation, police said in a statement.
"SO15 are now carrying out the investigation because of their expertise in the management of investigations with international dimensions and an established liaison network abroad," the Metropolitan Police said in a statement.
Police said that the investigation was in early stages and that officers "remain open-minded about the motive".
Arwani's family dismissed speculation that his opposition to the Assad regime could have been a factor in his murder.
"We have no idea what happened," Arwani's daughter Elham Arwani, 23, told newspaper the Evening Standard.
"Any Syrian who is free and who knows the truth is against Assad. It's not going to be because he was against Assad. It must be for another reason, but we can't think of anything."
Arwani's son Murhaf said in a statement that the family were in a "state of shock" and appealed for anyone with information to come forward.
"He was the most peaceful man you could ever wish to meet. He just loved to help people. He did not care what your background, race or status was," Murhaf Arwani said.
"He did not care if you were rich or poor. He just wanted to help people in need."
Arwani reportedly fled Syria as a teenager after surviving the 1982 Hama massacre, in which the current president's father Hafez al-Assad sent troops to brutally crush an Islamist uprising.
From 2005 to 2011 Arwani was a preacher at the An Noor mosque in Acton in West London. The mosque said in a statement he would be "sadly missed."
Friends and supporters of Arwani paid tribute to him on social media, and former Guantanamo Bay detainee and activist Moazzam Begg wrote on Twitter "May Allah have mercy on him."