A police helicopter searched the streets of Dunstable on Thursday night after two men were seen acting suspiciously.
But after a comprehensive search, it failed to spot the suspects and no actual offence was discovered.
Eyewitnesses were active on social media discussing the helicopter, which was still actively searching at 11pm.
A Beds police spokesman said: “We were called to reports of two suspicious men seen on a construction site in Church Street at about 10pm last night [Thursday].
“Officers attended and carried out an area search with assistance from the helicopter however no offenders were traced and no offences found to have been committed.”