Killed : Police are investigating the alleged murder of Syrian-born imam Abdul Hadi Arwani . A fourth person has been arrested over the alleged murder of a Syrian imam who was shot dead in his car on a London street . Police announced today that they had arrested a 36-year-old man on suspicion of conspiracy to murder Abdul Hadi Arwani , who was killed in Wembley two weeks ago . A Jamaican businessman has already appeared in court charged with Mr Arwani 's murder , while a man and a woman were arrested this week on suspicion of terror offences . The father of six , who was an imam at a controversial mosque in west London , was found dead in his black Volkswagen Passat on April 7 . Leslie Cooper , 36 , appeared at the Old Bailey on Thursday , where the court was told that Mr Arwani , 48 , was lured to a meeting with a potential customer for his construction business before being killed . Burnell Mitchell , 61 , the brother of Boney M 's lead singer , was arrested this week on suspicion of conspiracy to murder and the commission , preparation and instigation of acts of terrorism . A 53-year-old woman was also arrested on suspicion of the commission , preparation and instigation of acts of terrorism . They are both in Metropolitan Police custody while counter-terror officers continue to investigate Mr Arwani 's killing . Police said in a statement today that they had arrested the fourth suspect , a 35-year-old man , on Friday , before releasing him on bail today . Suspects : Leslie Cooper , left , appeared in court charged with murder while Burnell Mitchell , right , has been arrested on suspicion of terror offences . Mr Arwani was previously a preacher at the An-Noor mosque in Acton but resigned after he apparently fell out with other community leaders . The mosque was founded by Mr Mitchell 20 years ago after he converted to Islam , and he remains a trustee of the centre as well as a director of the company which owns its premises . Mr Mitchell , whose sister Liz Mitchell was the lead singer of Boney M , was brought up a strict Christian before changing faith and becoming known as 'Khalid Rashad ' . Both his home and the mosque were searched by police last week as part of the investigation into Mr Arwani 's death . Mosque : Police standing outside the An-Noor cultural centre in Acton earlier this week . The Syrian-born imam fled his home country in the 1980s and became an outspoken opponent of president Bashar al-Assad 's regime before his killing . Mr Arwani 's son Murhaf said last week : 'He just loved to help people . He did not care what your background , race or status was . 'He did not care if you were rich or poor . He just wanted to help people in need . 'He spoke up and out against the crime of terror and oppression wherever he found it . He was an advocate of peace for all and he showed us this in the way he lived his life from day to day . ' Sorry we are not currently accepting comments on this article .
61 , arrested on suspicion of conspiracy to murder Abdul Hadi Arwani . Syrian imam was found shot dead in his car on a street in Wembley . Leslie Cooper , 36 , has already appeared in court accused of murder . Burnell Mitchell , Man , 36 , and a 53-year-old woman were also arrested on suspicion of terror offences .