The Bradford sisters missing with their nine children were stopped from leaving the UK in March, ITV News has learned.
Their trip to Saudi Arabia was rebooked for May but there is no suggestion they were intending to travel to Syria at that time. Police are now trying to work out when the trip was planned.
Neighbours have identified this man as the brother of the three women thought to have fled to Syria with their nine children.
It is thought that police were already concerned about his whereabouts.
The family's lawyer has urged him to get in touch and send them back if they have crossed the Syrian border.
Speaking from Pakistan, one of the husbands of the missing Bradford thought to be heading to Syria has told ITV News of his worry.
Here's what we know about the Bradford family of 12 who are feared to be travelling to Syria.