(CNN) -- Aisha Gadhafi, the daughter of Libya's deposed strongman Moammar Gadhafi, asked the International Criminal Court Tuesday to accept "concrete information" she believes may help her brother.
Saif al-Islam Gadhafi, once seen as his father's heir apparent, was captured in November after the fall of the regime in August and is being held in the Libyan city of Zintan.
He was facing an arrest warrant from the ICC for alleged crimes against humanity at the time of his capture, and the court, based at The Hague, in the Netherlands, is still seeking to prosecute him.
Conflicting reports emerged a week ago about whether he would be taken to a court in Tripoli to face trial, and the ICC said it had not yet decided if he could be tried in Libya.
The application filed with the ICC by lawyers acting for Aisha Gadhafi says she "wishes to protect the interests of her brother ... whose exact whereabouts are presently unknown to her and whose fate is currently the subject of confidential litigation."
She wishes "to present concrete information which she believes will assist the pretrial chamber in determining the appropriate course of action it should take," the application says.
The "specific" information she holds will "assist the pretrial chamber in determining whether the Libyan authorities truly desire to provide Saif al-Islam Gaddafi with effective legal representation or to afford him a fair trial," the document states.
Aisha Gadhafi's information is based on her attempts to contact her brother through Libyan prosecutors and the International Committee of the Red Cross, in order to find out about his welfare and assign him a lawyer, the appeal says.
She also held two telephone conversations with the deputy prosecutor of Libya, from which it can be inferred that the Libyan authorities "refuse to deal with international legal counsel," it adds.
The ICC initially demanded that Libya hand over Gadhafi for trial after his capture, but then opened the possibility that he could be tried in Libya.
ICC prosecutor Luis Moreno-Ocampo said on a visit to Tripoli that Libya had the "right" to try him if it could prove it could do so fairly, with ICC judges to decide.
The ICC asked Libya last month whether Gadhafi was arrested because of the international warrant, if he was being held incommunicado, and if an ICC representative could meet him.
It also asked when and where a court-appointed expert could examine his physical and mental health, and whether and when they planned to hand him over to the court, giving Libya until January 23 to respond.
Libyan officials have submitted a confidential response to those questions, the ICC said in a statement last week.
In August, as her father's regime crumbled, Aisha Gadhafi fled to Algeria along with several other family members.
She is a onetime U.N. goodwill ambassador, as well as a lawyer who assisted in the defense of deposed Iraqi dictator Saddam Hussein, who was hanged in 2006.
Another brother, Saadi Gadhafi, has been granted asylum in Niger.
A third brother, Khamis Gadhafi, who led an army brigade blamed for the massacre of prisoners in a warehouse outside Tripoli, was killed in a late-August battle in northwestern Libya, rebel commanders said. A fourth brother, Saif al-Arab, was reported killed in a NATO airstrike in April.
Moammar Gadhafi himself died after his capture by anti-regime forces near Sirte in October.
CNN's Bharati Naik and Laura Smith-Spark contributed to this report.