I believe there is a well-established tenet that fraud vitiates all contract (bond). CONSTRUCTIVE TRUST - as I understand it is formed in several ways, but often it is done by the beneficiary interloping into the trust operations by behaving or taking inappropriately (misdeed) responsibilities properly attended to by the trustee. The result of the CONSTRUCTIVE TRUST is typically a suit by the trustee against the beneficiary. What I was told is simply,
The trustee sues the beneficiary all the time!