Beijing prosecutors approved the arrest of a man for intentional homicide on Monday, after he allegedly attacked 20 children with a hammer at a primary school earlier this month.

Besides announcing the arrest, prosecutors from Xicheng district said in a news release that they will highlight the legal protection of children and step up efforts to combat those seeking to harm them.

The man, surnamed Jia, worked as a maintenance worker at the No 1 Affiliated Elementary School of Xuanwu Normal School in the district. He allegedly rushed at a group of children with a hammer on Jan 8 after learning that his employment contract would be terminated.

The incident left 20 children injured, three of them seriously.

Jia, 49 and from Heilongjiang province, had been employed via an agency to work in the maintenance department at one of the school’s campuses. His contract was to end this month and the agency had decided not to renew it.

Officials from the district held a news conference on the night of Jan 8, saying that security at all schools in the district had been stepped up, and schools had been instructed to run thorough security checks on school workers.