All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is not permissible to accuse people with what is mentioned or with anything else without evidence. An accusation regarding one's honour is more serious than others, as this is defamation to one's reputation, and an insult which causes losing one's dignity and being harmed in regard to one's sustenance. Allaah Says (what means): {...you counted it a little thing, while with Allaah it was very great.}[Quran 24:15]. Allaah further Says about those who accuse other people of fornication or adultery without evidence (what means): {Why did they [who slandered] not produce for it four witnesses? And when they do not produce the witnesses, then it is they, in the sight of Allaah, who are the liars.}[Quran 24:13]. Furthermore, it is confirmed that the Prophet said: "If people are given rights just based on claims and without evidence, the blood and wealth of many people would be taken unjustly." [Al-Bukhari and Muslim]
Therefore, it is not permissible for a manager to take a decision to fire the accused without any clear evidence which can not be doubted. His decision should not be based on assumption, doubt or a mere accusation without evidence; as an allegation by itself could not be proven as an accusation especially if the accused is known to be religious and has a good moral conduct. Moreover, firing him from work should be not be linked to sins that the employee might have committed, even if that is proven against him. A person may sin and then repent, and Allaah accepts the repentance of the people who repent.
Allaah Knows best.