The initially released surveillance video of the recent attempt to assassinate President Donald Trump was blurry and incomplete. Posted a short time after the incident, it showed Cole Allen, the accused would-be assassin, charging a security site at the April 25 White House Correspondents’ Dinner in Washington. The fuzzy images showed Allen, shotgun in hand, dashing through the metal detectors that had screened people going into the dinner but were then being disassembled. The video did nothing to explain what happened before or after.

Then, after Allen was charged with attempting to assassinate the president, Jeanine Pirro, the U.S. attorney for the District of Columbia, released a clearer version of the crashing-the-metal-detector video. The sharper video clearly showed Allen’s run, plus the muzzle flashes of one Secret Service agent firing multiple times at Allen at close range (and missing).

The newly released video showed one more detail that could be critical to the case. Longer than the original version, it showed Allen, wearing the long coat under which he concealed a 12-gauge pump action shotgun and a .38 caliber semi-automatic pistol, walking in the hallway toward the metal detectors before ducking into a side room. A zoom-in showed a security agent with a bomb-detection dog following behind Allen. The dog seemed clearly to be tracking Allen, and it walked into the room behind the gunman.

The dog’s handler stood in the hallway watching through the door before appearing to give a little tug on the dog’s leash. The dog came back into the hallway. The agent kept standing there, looking inside the room, before the dog moved again to the entrance into the room. During this time, the agent seemed to be talking to someone who was off camera.

Then the dog came back, the agent turned to his left and the two began walking down the hallway in the direction away from the metal detectors.

It was at that moment — right as the dog and the agent handler turned away — that Allen, no longer wearing his long coat and holding the shotgun in ready position, burst out of the room and ran through the metal detector. The rest of the video is the now-familiar scene of Allen running and agents reacting.

So what does all this mean? It means it would be great if dogs could talk. What was it about Allen that caught the dog’s attention? In a CNN interview, Pirro referred to the dog as a “bomb detection” dog. It is not clear if the dog was also trained to detect firearms ammunition. If so, there was a lot to sniff: According to court documents, Allen had nine cartridges in the shotgun’s magazine, plus six more in a Velcro carrier attached to the gun, and 10 more in a small leather bag. He also had 10 rounds of ammunition in the .38, plus two additional magazines, each with nine rounds.

In any event, the dog was clearly interested in Allen. Now, since the dog unfortunately cannot tell us exactly what was going on, the security agent handling the dog could be one of the most important sources of information in the investigation. What did the agent see in that room? What was the agent saying, and to whom? Did Allen say anything? What did the agent think the dog had focused on? What did the agent observe Allen doing?

And finally, why did the agent think the situation did not present a threat? After watching the dog and whatever was going on inside the room, the agent turned with the dog to walk away. It was only a second later that Allen burst out of the room, armed to the teeth and heading toward the metal detectors.

There is a lot for prosecutors and investigators to go through in this case. At the moment, it appears the dog-handling agent could be the most important two-legged witness to the attempted assassination of the president of the United States.

This content originally appeared on the Washington Examiner at washingtonexaminer.com/daily-memo/4554314/whcd-shooting-need-dog-story/.