What is the ruling on one who always thinks ill of people and directs accusations at a person without him being present or hearing his opinion?

It is not permissible to harbor ill-will or suspicion towards people without clear evidence, due to Allah Almighty's saying: (O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin) and the Prophet's (peace be upon him) saying: "Beware of suspicion, for suspicion is the falsest of speech." Accusing people in their absence is forbidden backbiting according to the Quranic text: (And do not backbite each other), and His (peace be upon him) saying: "Backbiting is your mentioning of your brother what he dislikes." Those present must not listen to this backbiting, but rather advise the one doing it or turn away from him.