"... the incident on Jan. 6 started out routinely, as the three ships entered the strait, but when five Iranian boats began acting provocatively Adler ordered his sailors to man their weapons as he tracked the Iranian speed boats.
"We progressed on, we saw these ... small boats coming in at us," Adler said. "So instead of going by us, which we would have [expected] with smugglers, they were now going down the sides of the ships. So that indicates, you know, some more proactive maneuvering."
As the Iranian boats surrounded the U.S. ships, the Americans received a radio transmission in heavily accented English.
"I am coming to you. You will explode in a few minutes," the voice on the transmission said, and with the small Iranian boats surrounding their ships, the U.S. commanders had to take the apparent threat seriously.
"When I heard it, it just raised my awareness level. That the threat level seemed to perhaps increase when you combine it with the maneuvering of the vessels and the fact they would not respond to our warnings and interrogations," James told ABC News.
But Adler and James, who heard the transmission in the heat of the confrontation, said they disagreed.
"I think it's too coincidental that it wasn't from one of the ships, or the boats near by us," Adler said.
We expressed similar thoughts a couple of days ago:
The timing of that call suggests someone who was doing more than simply monitoring radio traffic on Channel 16. Under existing rules of engagement (ROE), American warships initiate radio contact well before approaching ships enter their inner defensive perimeter. Based solely on bridge-to-bridge communications, the intruder would have only a general idea of the vessels' location. His threatening call, at the height of the incident, seems hardly coincidental, and appears to have been based on more than VHF radio traffic.
By comparison, an IRGC command element, located on a nearby, Iranain-controlled island (or another naval vessel) would have detailed knowledge of the operational plan, and--with access to other communications channels, ELINT data and radar plots--an excellent idea of how the encounter was unfolding. With that information, it would be easy to make the radio call, at exactly the right moment.
It would also be relatively simple for Iranian linguists to mimic the well-known "monkey," creating plausible denial for their involvement. Tehran has used deceptive radio broadcasts in the past, to great effect. During the Iran-Iraq War, Iranian SIGINT units operated dummy radio networks, which passed bogus information that was intercepted by the Iraqis, causing them to deploy troops in the wrong areas. Given Iran's past proficiency in electronic deception, finding someone to imitate the heckler would be a piece of cake.
From their position on the bridge (or in their ship's Combat Information Center), Captain Adler and Commander James clearly perceived the Iranian boats as a threat, and the mysterious radio call was a part of the on-going IRGC operation. It the heat of the moment, it was a logical (read: the only) conclusion to make.
It's also worth remembering that the two commanding officers didn't based their tactical assessment solely on the VHF transmission--they had information from other sources--sources they aren't going to discuss with ABC News. Based on that information (and years of professional experience), they took action deemed appropriate for a serious situation. And, by all accounts, they made the right call.