The husband of special constable Nisha Patel-Nasri has been remanded in custody after appearing at the Old Bailey charged with her murder.
Fadi Nasri, 33, of Alderman Court, Barnet, north London, spoke only to confirm his name.
He was in the dock alongside Rodger Leslie, 37, of Chesterfield Flats, Bells Hill, Barnet, also charged with murder.
Tony Emmanuel, 41, of Clements Road, East Ham, and Jason Jones, 35, of Hathaway Crescent, Manor Park, east London, who are also charged, appeared via videolink.
Mrs Patel-Nasri, 29, was stabbed to death outside her home in Wembley, north-west London, in May last year.
Following the brief hearing before Judge Brian Barker, the Common Serjeant of London, all four men were remanded in custody.
A further hearing is expected to take place in June.
