MINNEAPOLIS — Minnesota Public Radio provided additional details of allegations of sexual harassment against humorist Garrison Keillor on Tuesday, saying his alleged conduct went well beyond his account of an accidental touch of a woman’s bare back.

MPR said in a statement that Keillor was accused by a woman who worked on his “A Prairie Home Companion” radio show of dozens of sexually inappropriate incidents over several years, including requests for sexual contact and explicit sexual communications and touching.

MPR said the woman, whom it has not identified, detailed the allegations in a 12-page letter that included excerpts of emails and written messages. MPR said as it attempted to investigate the case, Keillor and his attorney refused to grant access to his computer, emails and text messages.

Keillor did not immediately respond to an emailed request for comment. He has said in recent weeks he was in negotiations with MPR over separating the two sides’ business interests.

MPR released its statement just as its news division, MPR News, was airing a lengthy investigation of allegations against Keillor.

In a note to members Tuesday afternoon, MPR President Jon McTaggart said the separation was painful.