Police investigating the murder of Syrian preacher Abdul Hadi Arwani in north-west London have arrested a 53-year-old woman on suspicion of terrorism.
Metropolitan Police added a 61-year-old man who was previously arrested on suspicion of Arwani's murder has been further arrested on suspicion of the commission, preparation and instigation of acts of terrorism.
Both suspects remain in police custody for questioning.
Elsewhere, a 36-year-old man has appeared in court charged with the murder of the father-of-six who was found shot dead in his car in Wembley on 7 April.
Leslie Cooper is due to stand trial in October accused of the murder of Arwani, who was known to be an outspoken critic of Syrian President Bashar al-Assad.
As part of the investigation, police conducted a search of the search of the An Noor Cultural and Community Centre, a mosque in west London.
A Scotland Yard spokesperson said: "Officers are fully aware of the sensitivities of conducting this search at this time and would like to thank the local Muslim community for their support and patience thus far in the necessary investigations that have occurred to date.
"This remains a murder investigation and a search for the truth; it is therefore vital that the investigation is thorough which includes a detailed searches of premises.
"Community leaders have actively provided advice and support throughout this investigation and continue to provide guidance in relation to the sensitivities of conducting the search at the An Noor Cultural Community Centre."