Former prime minister Bhutto was killed in 2007 in Rawalpindi as she came out of a park after addressing an election rally.
Musharraf, 71, was president of the country at that time but he resigned in 2008 under popular public pressure.
Later, he was implicated in Bhutto's murder case in 2010.
Dawn reported that case against Musharraf was built on four witnesses, including former interior secretary Syed Kamal Shah, former director general of the National Crisis Management Cell (NCMC) retired Brigadier Javed Iqbal Cheema, former IB director general retired Brig Ejaz Shah and the US lobbyist Mark Siegel.
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Kamal Shah and Cheema had recorded their statements before the anti-terrorism court in January this year.
Musharraf's lawyer Ilyas Siddiqui claimed that both Shah and Cheema did not utter a single word in their testimonies implicating Musharraf.
The only witness the Federal Investigation Agency (FIA) has to produce is the US lobbyist Siegel, who according to joint investigation team (JIT) report held Ejaz Shah responsible for the attack.
The JIT report claimed that Siegel alleged in his statement that Bhutto had sent him an email on October 26, 2007, in which she expressed her sense of insecurity.
She also wrote that if something happened to her, she held Musharraf responsible as well as the individuals mentioned in her letter to Musharraf on October 16, 2007.
In that letter, she had named Brig Shah, retired Lt Gen Hameed Gul and Chaudhry Pervaiz Elahi.
Siddiqui said if Siegel sticks to his statement, his testimony will simply provide circumstantial evidence of Musharraf's guilt.
It had been three years since he was summoned but he never appeared due to security reasons.
The prosecution informed the court a couple of months ago that he was ready to testify through video-link but it has not materialised so far.
Siddiqui said that Musharraf might move an application for his acquittal in the case as the evidence presented so far was 'weak'.