asif malik , 31 , his partner sara kiran , 29 , their daughter zoha , seven , and their three sons essa , four , zakariva , two , and yahya , one , were all caught on camera on a cross-channel ferry .
they left their home in slough , berkshire , without mentioning any holiday or travel plans to family members , which is out of character , police said .
police say mr malik was a member of the banned group al-muhajiroun and a ` champion for sharia .