The UN is concerned about the fact that the Egyptian government has failed to open a proper investigation into the circumstances surrounding the death of prominent economist Ayman Hadhoud.
It has also expressed concern over allegations of enforced disappearance, arbitrary detention, torture and denial of adequate medical care, reports the Committee for Justice.
Hadhoud was detained by security services in February and was later sent to a psychiatric hospital in Cairo where he died.
His brother has said that Ayman had no history of mental illness and had criticised authorities publicly.
After his death, an investigation by Amnesty International said there had been evidence to suggest he had been tortured or ill-treated before his death. The probe was based on official records, witness interviews and independent experts who examined leaked photos of his corpse.
In May, the US State Department said that his death requires a "thorough, transparent, and credible investigation."
Egypt has carried out its own probe into Ayman's death, but the autopsy confirmed that he died due to a chronic heart condition and that his body was free of any marks of injury, contrary to what Amnesty concluded.
Egypt has a history of denying it has political prisoners even though rights groups say there are tens of thousands.
The Interior Ministry initially tried to say that Ayman was arrested after attempting to break into an apartment and was sent to the hospital because of his erratic behaviour.
His brother said they were initially unable to find him and were only informed that he had died one month after he died.
After Ayman was arrested in Zamalek, Cairo, on 6 February his family were informed two days later that he was being held at the Amiriya police station however when they visited him there the police denied that he was being held inside.
At the time, 17 Egyptian human rights organisations called for a thorough and transparent investigation into his death.
The family has still not received an official autopsy report on Ayman's body despite attempts by his lawyer to retrieve one.
The UN has confirmed that Ayman was not given appropriate and timely medical care which may have contributed towards his death after a nurse called a doctor to report his health was deteriorating and medicine was prescribed remotely but with no examination.
Ayman was not transferred to a properly equipped hospital until five hours later, despite his health deteriorating further.