An explosion on Thursday killed one and injured 21 in a busy street in Tongren, Southwest China's Guizhou Province. The bomb was hidden in a rubbish bin in the city's commercial hub ,where lots of shops and restaurants are concentrated. The ear-splitting blast was heard around 12:50 p.m.,said a local newspaper, citing witnesses. The power of the blast shattered nearby shop windows and ripped the stainless steel rubbish can to pieces. One passer-by,identified only as Zhang,said she was shocked by the noise and saw a lot of pedestrians lying on the ground when she got to the scene. Thirteen of the injured were taken to a local hospital after the explosion. A doctor there said five were in serious condition but already out of danger after emergency treatment. The others were just slightly hurt. "The cause of the explosion is still unknown", said an officer with the Tongren police, but refused to speculate as to the cause. Which of the following statements is true according to the passage?
One passer- by, identified only as Zhang, saw the man throwing a bomb into a bin. Some customers in restaurants were injured. The writer didn't get to the scene. All customers in shops got hurt.