Late last year, Morgan Stanley got a tip: Reporters were asking about allegations that a high-profile executive, the former congressman Harold E. Ford Jr., had harassed a female journalist.

Morgan Stanley conducted a quick investigation, interviewing the accuser and Mr. Ford, who denied the allegations. According to Morgan Stanley officials briefed on the internal process, the Wall Street bank concluded that it was a he-said, she-said situation and didn’t find proof of harassment.

Then Morgan Stanley fired Mr. Ford.

Why? It depends on whom you ask.

The Morgan Stanley officials briefed on the process say that amid a national outcry over sexual harassment, the bank had little choice but to fire Mr. Ford after it learned of the allegation. Even though the harassment charge was never corroborated, they said, the bank found evidence that Mr. Ford had misled executives about some of his behavior, which itself constituted cause to remove him. And they say Mr. Ford already had received a final written warning about abuse of his expense account and other conduct.

Mr. Ford and his lawyer say there’s a different explanation: that Morgan Stanley used the journalist’s allegations as a pretext to fire him simply because he was disliked internally.