Yes you're technically right that it's alleged, but again, I think the quotes are sufficient. There's ample evidence of this, as shown in the unsealed document that Harvard fought to keep secret.

This sort of headline is massively irresponsible these days, when most people learn most "facts" from skimming headlines on Facebook and Twitter and inferring the stories. When the headline is all you see, it needs to be as fair as possible. To respond to the other response here, quote marks give you no information about the veracity of the statement. The quote could be from a baseless accusation or from an independent report. The BBC should do better.

It is in quotes..

That's how the BBC does their headlines. Anytime something is in quotes, prepend the headline with "Someone says:". For whatever reason they won't write headlines longer than 6 or 7 words.