Activist Anas El-Assal, known for aiding the injured during past clashes in Tahrir Square, was reportedly kidnapped Friday at dawn by unknown assailants.
The activist was found Saturday night in Al-Hilal Hospital suffering from deep bruises and traces of six injections.
According to the victim's brother, El-Assal was attacked when he opened the door to their home. He was sprayed in the face until he lost consciousness, eventually awaking in an empty cell.
"He was attacked and injected continuously during the interrogation with an unknown substance," said his brother, Malek.
The substance was later identified as Tramadol, a drug that anti-revolution figures had frequently accused Tahrir Square protesters of using.
El-Assal is currently at a centre where he is receiving treatment for poisoning after suffering from an overdose of the drug. He is still hallucinating and cannot remember how he arrived at the hospital.
Sara El-Assal, his sister, has accused the hospital of refusing to register her brother's name on entry. The hospital later agreed to take his name, but requested that his family file a report on the incident.
His sister further stated that his health condition had declined since he was injured during the May clashes in Cairo's Abbasyia district, when his arm was broken in a fight with military personnel.
The Abbasiya clashes took place outside of Egypt's Ministry of Defence following a week-long sit-in that began on 2 May. Initially instigated by supporters of disqualified Salafist presidential candidate Hazem Abu-Ismail ('Hazemoun'), the clashes were later joined by a number of anti-SCAF protesters.
El-Assal, along with hundreds of other activists, currently faces charges of illegal assembly and violence against military personnel during the Abbasyia clashes.
According to a Facebook page established in solidarity with El-Assal, the young activist was known for the role he played in aiding the injured during major clashes in Cairo's Mohamed Mahmoud Street last November and the Cabinet clashes in December, along with the more recent Abbasyia events.
Lawyer and activist Ragia Omran, for her part, told Al-Ahram's Arabic-language news website that the reasons for the alleged attack on El-Assal remain vague. He would not, however, represent the first activist to be kidnapped.
Omran expressed doubt that El-Assal's abduction was connected to his trial, the next session of which is slated for Monday.
Activist Badreya Mahmoud, who El-Assal was protecting from military personnel when he was arrested during the Abbasyia clashes, also claims to have been kidnapped during an 18 July protest against the Syrian regime held outside Syria's embassy in Cairo.
El-Assal's only defence witness – and an Abu-Ismail supporter – told Al-Ahram's Arabic-language news website that, during her kidnapping, she had been tortured, interrogated about her activities with the Hazemoun movement, and threatened with violence in the event that she was "seen in the square again."
Mahmoud later accused police of refusing to let her file a report following her release documenting evidence of the torture she allegedly underwent.
Recently, a number of incidents of activists being kidnapped by unknown assailants have been reported. Many activists accuse Egyptian security forces of standing behind the phenomenon.
Ahmed Ibrahim, a member of the 'No to Military Trials' campaign, claims he was kidnapped on Friday and questioned about the campaign and its members. Ibrahim says he was released a few hours later.