The claim was made in a preliminary report prepared by the Bomb Disposal Squad (BDS) on the suicide attack.
Sources said that ball bearings were also found at the site regarding the preliminary report prepared by the Bomb Disposal Squad.
BDS officials said in their report after a preliminary investigation that commercial explosives were used in the suicide bombing.
At least four people, including three Chinese teachers, were killed and several others injured in a suicide attack on a van at Karachi University.
A female bomber blew herself up at the gate of the Confucius Institute, which teaches Chinese language at Karachi University, just as it was about to enter the van of Chinese teachers.
The blast was so loud that its sound could be heard in the distance. The windows of nearby buildings shattered and panic spread among the people. The van caught fire, killing four people and injuring several other banned Baloch Liberation Army claimed responsibility for the attack. Dari accepted.
As soon as the incident was reported, Rangers police fire brigade and other rescue agencies rushed to the spot and shifted the bodies and injured to the hospital. The registrar of Karachi University said that three Chinese teachers and a van driver were killed in the blast.