The problem I see is the controller asked the Helicopter if they had the CRJ in sight, but he never said WHERE HE WAS OR WHAT HE WAS DOING! The controller should have told the Helicopter that the CRJ was circling to RWY 33. The helicopter said he had him in sight, but he really had the Jet in sight that was landing on RWY 1.
Had the controller told him: Traffic ahead and to your left landing runway 33 is a CRJ report him in sight, then the helicopter crew would have LOOKED to their left and saw him. They unfortunately were looking straight ahead at a different plane.
The controller is going to take a major blame for this one unfortunately for not being more detailed. Those Helicopters literally fly directly in the path of those RWY 33 arrivals so as a controller you have to be EXACT!!!!
Another problem I see is the expectation bias. As controllers in that scenario, we want to hear the Helicopter say "traffic in sight and we will maintain Visual Separation. These Helicopter Pilots know we need to hear them say that (it's required), so they will say this just because even though they might not really have the aircraft in sight. They are just saying what we want to hear. If they don't, then we stop their forward progress or make them turn out. Comment from instagram