Transcript for Questions remain 2 weeks after deadly ambush in Niger

It was Monday in the rose garden when the president was asked about the deaths of four U.S. Servicemen, part of a green beret team, all special ops, killed in an ambush in Niger. 12 days had gone by with no comment from the president. It was there that the president talked about those solemn phone calls. Tonight, the Pentagon has revealed an investigation. How did these four men die, and did they have the intelligence and the backup that they needed to get out? Here's ABC's chi investigative correspondent Brian Ross tonight. Reporter: The deadly ambush in this remote African village happened more than two weeks ago. But tonight, the Pentagon is still not providing a full and cogent narrative of how four American soldiers died after being attacked by an overwhelming force of more than 50 militants. Officials said the full investigation, only announced today, is still ongoing. Subsaharan Africa is a very difficult place to operate. So, we will -- we'll investigate this. We'll have conclusions and those conclusions will be presented. I'm not prepared to go further. Reporter: Two key questions remain tonight. One, did the unit have the proper advance intelligence and backup air and ground support in case something went wrong. Officials said the unit did not expect to be in combat. Over the last six months we have conducted 29 partner patrols in this general area, without contact of any kind. Reporter: A second question. Did sergeant la David Johnson get left behind when the rest of the unit pulled out? His body was not recovered for at least 20 hours. It took us a little while to do that, but we didn't leave him behind and we searched until we found him and we brought him home. Reporter: U.S. Forces have been in Niger for the last four years, as the threat from this terror group has escalated, with its leader last year pledging allegiance to ISIS. There's a reason we have U.S. Army soldiers there and not the peace corps, because we carry guns. Reporter: As controversy swirled over the ambush in Niger, the president was taking credit for U.S. Victories against ISIS. I totally changed the attitudes of the military and they have done a fantastic job. Yeah, ISIS is now giving up. They're giving up. They're raising their hands. They're walking off. Nobody's ever seen that before. Why didn't that happen before? Because you didn't have trump as your president. Brian Ross with us again tonight. And bruin, we took note that senator John McCain said today that he may need a subpoena to get answers on Niger? Reporter: The senator told ABC news he did not think the administration was being up front about what happened in Niger, even suggesting, as you say, that as chairman of the armed services committee, he might issue a subpoena to get the information he wants and needs. Brian Ross with us tonight. Brian, thank you.

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