The crew were concerned about the behaviour of a number of pax, all of a similar ethnic appearance.
1 Pax was seen with a mobile phone, but no one actually saw him using it.
Lots of different issues caused the crew some alarm, which taken in isolation, you wouldn’t even think about. Capt decided to call ahead and ask for the flight to be met by police.
No one was arrested, although a large number of pax were spoken to in respect of the concerns of the crew. No one has done anything wrong.
Crews are asked to remain vigilant and it is easy to get paranoid. Call was made in good faith, but there is no evidence that anyone has done anything wrong, or was even considering it.