BBCThe BBC knew about a police investigation into DJ Scott Mills in 2017, the corporation has confirmed.
But the Radio 2 presenter was sacked after "new information" about his conduct came to light in recent weeks, the BBC said.
Mills was previously questioned by police over historical allegations of serious sexual offences, but no charges were brought after prosecutors decided in 2019 there was insufficient evidence to proceed with the case.
Mills has not yet responded to repeated requests for comment.
BBC News understands that the director general at the time of the police investigation, Tony Hall, did not know about the allegations.
The BBC's statement on Wednesday came after mounting pressure on the broadcaster to explain what led to the Radio 2 DJ's sudden departure.
In a statement, a BBC spokesperson said: "Scott Mills had a long career across the BBC, he was hugely popular and we know the news this week has come as a shock and surprise to many.
"We also recognise there's been much speculation in the media and online since Monday. We hope people understand that there is a limit to what we can say because we have to be mindful of the rights of those involved.
"What we can confirm is that in recent weeks, we obtained new information relating to Scott and we spoke directly with him. As a result, the BBC acted decisively in line with our culture and values and terminated his contracts on Friday 27 March."
The spokesperson added: "Separately, we can confirm the BBC was made aware in 2017 of the existence of an ongoing police investigation, which was subsequently closed in 2019 with no arrest or charge being made. We are doing more work to understand the detail of what was known by the BBC at this time."
The statement concluded that the BBC has made "a significant commitment to improve its culture, processes and standards".
"Last year, following an independent culture review, we set out the behavioural expectations for everyone who works with or for the BBC and we were clear action would be taken if these were not met."
On Monday, it was announced that the former Radio 1 presenter had been sacked by the BBC over allegations related to his personal conduct.
The allegations, first published on Monday by the Mirror, relate to the period between 1997 and 2000, police said, when Mills would have been in his mid-twenties.
On Tuesday, the BBC apologised for not looking into a separate allegation of "inappropriate communications" involving Mills, first reported in the Telegraph, raised by a freelance journalist last year.
