There was a small but important evolution in NBC News' story on Matt Lauer, who was fired Wednesday after becoming the subject of sexual harassment allegations.

In his initial memorandum to staff announcing the longtime anchor's departure, NBC News chairman Andy Lack said the precipitating allegations brought against Lauer, reported to management on Monday, represented "the first complaint about his behavior in the over twenty years he's been at NBC News."

Pressed by CNN later that day, however, an NBC spokesperson said, "We can say unequivocally, that, prior to Monday night, current NBC News management was never made aware of any complaints about Matt Lauer's conduct."

There is a key difference between those two accounts.

Through Lack, NBC initially claimed not one complaint had been made about Matt Lauer's behavior during his time at the network. In the second statement, however, NBC shifted slightly to claim current management was never made aware of any complaints, effectively leaving the door open to the possibility that other complaints had been made, and previous management was aware of them.

That second statement, by the way, came after Variety published a detailed story reporting "[s]everal women" claimed to have "complained to executives at the network about Lauer's behavior," but that those complaints "fell on deaf ears given the lucrative advertising surrounding 'Today,'" a discrepancy we noted at the time.

In another memo to staff sent on Friday, Lack implicitly maintained no complaints about Lauer had been brought to management, addressing why Lauer's behavior "wasn't reported sooner" and insisting, "[t]his week we saw that when an employee comes forward to report misconduct, the system works."

If the women interviewed by Variety are to be believed, that assertion is garbage.

Given the network's subtle, but important shift, in addition to the sheer volume of allegations now leveled against Lauer, the credibility of NBC News seems dubious.