A family of 12 has disappeared amid fears they have gone to Syria.
The group from Luton, which reportedly includes a baby and two grandparents, failed to return home from a holiday in Bangladesh.
Police said they are investigating and that "there is a suggestion that the family may have gone to Syria".
Bedfordshire police named the group as: Muhammed Abdul Mannan, 75, his wife Minera Khatun, 53, their daughter Rajia Khanom, 21, sons Mohammed Zayd Hussain, 25, Mohammed Toufique Hussain, 19, Mohammed Abil Kashem Saker, 31, his wife Sheida Khanam, 27, Mohammed Saleh Hussain, 26, and his wife Roshanara Begum, 24, along with three children, aged between one and 11.
In a statement relatives of the group spoke said they "can only think they have been tricked".
'Out of character'
They said: "We are devastated by the disappearance of these 12 and are very concerned for their safety.
"This is completely out of character and we are very worried of the danger they may now be in.
"Muhammed Abdul Mannan is elderly and both he and Minera Khatun have health issues.
"This just does not make any sense. We can only think they have been tricked into going there, it is no place for elderly or young people.
"We would urge any of them to please make contact with us or the police to let us know they are okay."
Failed to return home
They were reported missing after failing to return home from a holiday in Bangladesh in May.
They initially travelled to the country from Heathrow via Istanbul on 10 April.
A police spokeswoman said: "However they failed to return and were reported missing by a relative in Luton on 17 May.
"There is a suggestion that the family may have gone to Syria, however police have so far been unable to corroborate that information.
"Police are continuing with their enquiries and are working with relatives who are still in the UK."
The BBC said it is understood that Muhammed Mannan has diabetes, while his wife has cancer.