It's very old and basic law.Mere presence does not make a person guilty of a crime: 'Even if a man is present whilst an offence is committed, if he takes no part in it and does not act in concert with those who commit it, he does not become an aider and abettor merely because he does not endeavour to prevent the offence, or fails to apprehend the offender.' (Hale's Pleas of the Crown; so held in Rv Fretwell (1862) and other authorities).Presence coupled with doing or saying anything which assists or encourages the crime does.
The report is of what the 'business partner' did is plainly of what he wanted people to believe, it's,his version of events.It's missed out other evidence, rather more embarrassing to him.There wouldn't have been a case to go to the jury; it would have been stopped by the judge; on that alone, never mind the jury being sure he was guilty, if that's all there was.There's no crime. in such a case, of not stopping someone else committing a crime! However, evidence that one person acquiesced in the other's actions may be evidence tending to show that he had agreed to the commission of the crime and meant to encourage or actively assist in it.It tends to confirm other evidence of involvement. What we are not being told is what the other evidence was .In itself, and alone, what he did (or, rather, did not do) would not be enough.