Is the testimony of an employee or a partner in a company against another employee in the same company acceptable in Islamic jurisprudence, if he is the only one who can reveal the truth?

The testimony of an employee or a shareholder in a company regarding another employee in the same company is acceptable in Islamic judiciary, unless there are impediments to accepting the testimony, such as the witness being a disbeliever (kafir) or openly immoral (fasiq), or if there is animosity between him and the person testified against, or a close kinship between him and the person testified for, or if the witness is underage or insane.