NBC News has launched an internal investigation into Brian Williams’ statements about his reporting in Iraq, led by the head of its own investigative unit. Deadline confirmed the news just before a memo to staff from NBC News chief Deborah Turness came to light (read it in full below).

“As you would expect, we have a team dedicated to gathering the facts to help us make sense of all that has transpired,” Turness wrote. “We’re working on what the best next steps are – and when we have something to communicate we will of course share it with you.”

The news division’s Richard Esposito, a former editor at the New York Daily News, has been put in charge of the investigation. The late Friday reveal comes when old-think news managers believe readership is at its lightest, adding to the cynicism. News of Esposito spearheading the investigation curled the lips of some in the TV news biz who say he was involved with NBC News’s bungled report that a suspect in the Charlie Hebdo massacre had been killed, only to reverse that and say the situation was still unclear after which, the next day, Williams corrected the report on-air, saying the information provided by a source “turned out not to be correct.”

Meanwhile, the Twitter account of Rich Krell has been deleted. He’s the pilot who in an interview yesterday with CNN claimed, then retracted the claim, that he piloted Williams in the Chinook helicopter in Iraq in 2003 that Williams said was hit by a rocket-propelled grenade. Williams this week apologized on NBC Nightly News for falsely saying on the network’s air last week that he was in a helicopter hit by an RPG while embedded in Iraq in 2003.

And what of the soldiers who exposed Williams’ fabrication? They tell Stars And Stripes, which first broke the story, that they are “more or less satisfied” with Williams’ on-air apology. This, according to the report’s author Travis Tritten, who told CNN today, “I don’t think they want to see him fired at all.”

Sorry, guys — probably too late.

NBC News also is looking into Williams’ coverage of Hurricane Katrina, especially his reference to looking out of his hotel room in the French Quarter and “watching a man floating face-down.” The New Orleans Advocate already has launched an investigation into that claim, in the wake of this week’s news about Williams Iraq reports; the newspaper reports doubters have noted correctly that the Quarter remained largely if not completely dry during and after the hurricane, but photographs and news reports from the time indicate there was flooding around the Ritz-Carlton, where Williams stayed — shallow enough that the sidewalk below was clearly visible, but deep enough that a boat was seen bobbing in the water.

Today started badly for Williams, who already was having an epic bad week. While Williams was at a morning meeting to apologize to NBC News staff for the situation — NBC’s Sunday Beltway show anchor Chuck Todd described Williams as “pretty remorseful” at the meeting — CNN was kicking off its day with a big backpeddle on its report in which Krell backed up Williams’ story about taking fire in that helicopter. This morning, CNN reported Krell now wasn’t sure about his memory.

“The pilot was there but several other soldiers said ‘Brian was on our aircraft’ and this morning he is questioning his own memories,” CNN media critic Brian Stelter said to viewers this morning, adding that Krell now says his “nightmares of Iraq have resurfaced…and he is no longer standing by his story.”

Meanwhile, Williams’ evening-news anchor predecessor Tom Brokaw issued a statement denying a morning gossip column report that he’d called for Williams head on a platter over the situation.

Here is Turness’ full memo to staff:

All,

This has been a difficult few days for all of us at NBC News.

Yesterday, Brian and I spoke to the Nightly News team. And this morning at the Editorial Exchange, we both addressed the wider group. Brian apologized once again, and specifically expressed how sorry he is for the impact this has had on all of you and on this proud organization.

As you would expect, we have a team dedicated to gathering the facts to help us make sense of all that has transpired.  We’re working on what the best next steps are – and when we have something to communicate we will of course share it with you.

Since joining NBC News, I’ve seen great strength and resilience. We are a close-knit family, and your response this week has made that even clearer.

As a relentless news agenda marches on, thank you again for continuing to do what we do best – bring the most important stories of the day to our audience.

Deborah