The Boston Symphony Orchestra says an independent investigation into a sexual harassment allegation against conductor Charles Dutoit has found that the allegation was credible and uncovered at least three other alleged instances of misconduct.

The 81-year-old Grammy-winning conductor has strongly denied previous accusations, which span multiple cities over a four-decade period starting in the late 1970s and range from groping and kissing to, in one instance, rape.

The orchestra says the investigation found “credible” the allegations brought by Fiona Allen.  She is a former intern for the orchestra who is now chief executive of the Birmingham Hippodrome Theatre in the United Kingdom.

The orchestra didn’t describe the nature of the new allegations other than to say they too have been deemed credible.