with a former Blackhawk pilot and instructor...he commented that the controller was assured by the Army Helo (PAT25) that they had the "CRJ" in sight, but it'a likely that the plane they were looking at was one a couple of miles further behind the CRJ. The former Blackhawk pilot said that had the controller informed the PAT25 crew that the CRJ was actually at their altitude and just 1/2 mile away, then that crew could have been able to realize a collision was imminent and taken action to avoid the CRJ.
Perhaps we'll see recommendations in the future that ensure more specificity by controllers during such difficult circumstances, and restrictions on Army Helos wearing night vision googles around such busy airports.