MUAR, Malaysia - Police have launched a massive manhunt for the man who brutally bludgeoned and injured three pre-schoolers at Tadika Sinario in Lorong Haji Ali here.

Johor police chief Deputy Comm Datuk Mohd Mokhtar Mohd Shariff said police had mounted roadblocks and mobilised teams, including plainclothes policemen, detectives and traffic policemen.

He said all resources in the department would be deployed to nab the attacker.

"We believe he is of unsound mind and should not be allowed to remain free."

"No one in his right frame of mind would want to hit or hurt children with a hammer."

"I have also directed our intelligence unit and special branch members to collect all information regarding the attacker," he said, adding that he had also directed the Muar police to work with the Ledang and Batu Pahat police on this case.

DCP Mokhtar said roadblocks had been set up at many junctions within Muar town and all motorcyclists were being screened.

A traffic police officer said about 40 policemen and volunteer policemen were involved in the operation which began shortly after the horror attack.