A man was detained by Shanghai police on Wednesday after allegedly using a kitchen knife to kill two of his relatives and injure 11 people, including six students under the age of 10.

According to the local police, the suspect surnamed Zang, who is originally from Jiangsu Province, lived with his sister on Jinqian road, in Shanghai's Fengxian district.

Zang is accused of killing two women around 4:30 pm and then running to the Jinhui Primary School where students were just getting off school.

Five boys and one girl suffered head injuries and two were cut on the arm, said parents waiting at the hospital.  The youngest of the injured students is an 8-year-old student.

None of the six injured children were accompanied by any adult, the parents told the Global Times.

 The injured people are being treated at the Fengxian Central Hospital and their lives are not in danger, said police who are investigating the case.

A witness surnamed Zhang told the Global Times that Zang killed his sister and sister's mother-in-law after they refused to give him money. The father-in-law of Zang's sister called Zhang for help. "When I arrived, they were covered with blood and soon after we sent them to the hospital doctors confirmed their deaths," said Zhang.

Zang is said to be around 30 years old and 165 centimeters tall.

"He acted crazy and, mostly cut people on their heads," Xia told the Global Times. Another witness said he first injured two boys.

"I heard him saying, 'I killed people, why isn't anyone trying to catch me?'" said Xia, adding that people picked up tools, including iron shovel, kitchen knives and bricks, and started to chase the fleeing Zang.

Zang ran across several streets and was on the loose for nearly 20 minutes. One person was hurt when he tried to hit Zang on the head.

 "He was still trying to cut people when nearly 20 people pushed him to the ground in front of a supermarket," one of the witnesses said.

Over the past few years a number of young students have been killed by men at their school. 

On March 23, 2010, Zheng Minsheng, a doctor in Nanping, Fujian Province slashed 13 children at a primary school entrance, killing eight of them.