The assistant warden of a private religious school, under remand to facilitate police investigations into the brutal assault of a 'tahfiz' (religious school) pupil has a previous criminal record.

The 29-year-old staff of the religious school located near Kota Tinggi was convicted for theft and jailed 30 months about three years ago.

Kota Tinggi police chief ACP Rahmat Othman said the man had served time from the date of arrest on May 22, 2014.

"We have recorded statements from the school's principal, staff and fellow students," he said when contacted in Johor Baru today.

About 4pm yesterday, the suspect was picked up by a police team in Felda Lok Heng Barat in Johor Baru following a police report lodged by the 11-year-old victim's mother.

He was remanded for four days to facilitate investigations.

On Wednesday, the victim was warded at the Sultan Ismail Hospital in Johor Baru and the incident had since gone viral on social media.

The pupil was believed to have suffered pain in his legs for the past two weeks after he was allegedly beaten up by the suspect.

Yesterday, state health, environment, education and information committee chairperson Ayub Rahmat was quoted as saying the pupil's legs had to be amputated to avoid infection and that he was in a coma.

- Bernama