An anti-terrorism court issued warrants for former Rawalpindi police chief Saud Aziz and his deputy, Khurram Shahzad, who allegedly destroyed evidence by having the crime scene washed down less than two hours after the Dec. 27, 2007, assassination, The Guardian reported.
According to a U.N. report, the washing did "irreparable damage" to the investigation.
Aziz and Khurram, now retired, could not be reached Sunday. They are to be formally charged Dec. 11, along with five men already in jail.
Three years after Bhutto was killed in a suicide bombing as she left an election rally in Rawalpindi, her death remains unsolved.
Pervez Musharraf, who was then president, blamed a Taliban leader, but Bhutto's party charges that other forces, including the military, played a role. Bhutto's widower, President Asif Zardari, has vowed to expose her killers, but has made little progress.