Police are searching for three young brothers kidnapped by their father from a foster home in south London.
Detectives have appealed for any sightings of the boys and their father who they fear may have taken them abroad.
Police say the father Imran Safi, 26, may have abducted his sons because they were about to be officially adopted.
They believe he planned the kidnap with the help of others.
Eight suspects, including members of the family, have been arrested and questioned.
Mr Safi is said to have threatened the boys’ foster mother with a knife before driving off with them in his distinctive red Nissan Qashqai car in Coulsden Road, Croydon, South London, last Thursday afternoon.
Commander Jon Savell, of the Metropolitan Police, said: “We are concerned for the boys’ welfare, though we don’t believe there is imminent risk of harm. We would have expected to have found them by now.
“Their father used a degree of force to threaten their foster mother. She had minor injuries but she is very shaken.”
Hundreds of officers have been working around the clock to locate the boys – Bilal, aged six, Ebrar, five, and three-year-old Yaseen.
Anyone with information is asked to call police.