Police in Colorado stopped 25 cars and arrested and detained 40 innocent people over two hours as they turned their hunt for a bank robbery suspect into a frenzied blind search.

Handcuffing every adult at gunpoint, the intersection of E. Iliff Avenue and S. Buckley Road in Aurora, Colorado, turned into a chaotic scene as police swarmed the area looking for the suspected robber.

'Cops came in from every direction and just threw their car in front of my car,' said Sonya Romero, who was one of the drivers who had been handcuffed by police.

Taking a total of two-and-a-half hours to locate their suspect, police left the detained members of the public shaken.

'They had their shotgus out and their tasers,' said witness Ben Barker.

'They had five or six people line up one after another, they had them with their hands up and arms up like this and put them behind their backs, cuffed them and walked them away.'

Eventually police discovered a heavily armed man at the wheel of a white Ford Expedition who they described as their chief suspect and he was arrested.

His name has not been released.

'We didn't know if we were in the line of fire or what the hell was happening,' said Romero to KMGH

Police were responding to a 'reliable' tip that the culprit for the robbery was at the intersection stopped at a red light.

'We didn't have a description, didn't know race or gender or anything, so a split-second decision was made to stop all the cars at that intersection, and search for the armed robber,' said Aurora police Officer Frank Fania.

'Most of the adults were handcuffed, then were told what was going on and were asked for permission to search the car.

'They all granted permission, and once nothing was found in their cars, they were un-handcuffed.

'Once officers got to his car, they found evidence that he was who they were looking for.

'When they searched the car, they found two loaded firearms.

'It's hard to say what normal is in a situation like this when you haven't dealt with a situation like this.

'The result of the whole ordeal is that it paid off.

'We have arrested and charged a suspect.'

However, the Aurora police have come in for criticism because the suspect was apprehended last, was armed and over three dozen innocent bystanders were in the line of fire.

'Yes, we were very concerned by that,' said Fania.

'That is why my understanding is that the description of how we handled the tactics at the scene is that it was extremely well done.

'Investigative detentions are lawful for a reasonable period of time.'

Indeed, civil liberty experts were equally concerned as to the legality of the detentions.

'The concern is that the officers involved couldn't point to any of these people they stopped and articulate their suspicion for believing that you did something wrong,' said civil liberties expert Jim Miller.