SEBERANG PRAI, Penang - A man who attacked a woman in Penang at a bus stop for not wearing a headscarf is believed to be mentally ill, according to the police.

A video of the man slapping the woman at the bus stop in Sebarang Perai in Penang state went viral.

"Based on preliminary investigations, the police have found that the man is in his 30s and hails from Ipoh, Perak, and has had mental problems for 15 years," Seberang Perai Tengah district police chief Nik Ros Azhan Hamid told Utusan Online, the onlline edition of Utusan Malaysia daily.

The video had alarmed many people amid the rise of conservative Islam in Malaysia.

The victim, an Indonesian national who works at a factory nearby, was shocked when the man pushed her head using his hand, Mr Nik Ros said.

"The suspect then moved away after being scolded by the elder sister of the victim and several friends at the bus stop," he added.

The incident took place on Jan 6, when the suspect approached the bus stop at Taman Perwira in Bukit Tengah.

Mr Nik Ros said the suspect had earlier asked the woman where she was going before suddenly saying he dislikes women without headscarves.

The victim lodged a police report on advice from the police.

New Straits Times reported on its website that police have identified the man but have yet to make an arrest.

"We tracked down his house but he is no longer staying there. His uncle said he has not been sane for the past 15 years after he met with an accident," NST quoted Nik Ros as saying.

He added that the police will continue to search for the man.