The correct investigative strategy with suspects in a crime like this without direct evidence of their involvement would be to put them under surveillance. Of course if after 24 hours the surveillance team caught them red handed you’ve got your culprits. HOWEVER hindsight is great, had the airport remained closed for 24 hours before the police
caught their “man” they’d be pilloried for not acting quicker and over 100,000 more passengers would have been disrupted. There were clearly reasonable
grounds to arrest and investigate the incident.