What is the ruling on an agent who increased the price of a house to the principal without his knowledge, and what is the ruling on the witnesses to this transaction?

If an agency agreement is established, it becomes unlawful for the agent to resort to deception and lying in order to obtain an increase above the price of what he purchased for his principal, because agency is founded upon trustworthiness and honesty. If the agent deceives or lies to take more than the price, this is a betrayal that necessitates his repentance and the return of the excess amount to the principal. As for the witnesses, if they were aware of the reality of the matter, they have committed a sin by assisting in lying and deception. However, if the agent misled them, they are not held accountable.