Bhutto, the first woman prime minister of any Muslim country, was killed by a suicide bomber in 2007 as she was leaving an election rally.
Eight accused, including former military ruler Pervez Musharraf, have been charged in the assassination case.
Other accused include former Rawalpindi police chief Saud Aziz, then superintendent of police Khurram Shahzad and Taliban cadres Aitizaz Shah, Hasnain Gul, Muhammad Rafaqat, Sher Zaman and Abdul Rasheed.
Musharraf was granted bail in the case while all others are in jail.
Shah, Gul and Rafaqat have filed bail applications that will be taken up at the next hearing.
Musharraf, who was president in 2007, was formally charged last year though his government had blamed the Taliban for the killing.
The case was registered soon after the assassination but the trial has been proceeding at a snail's pace.