The family of a teenager, who is serving a 12-month prison sentence for insulting Johor Crown Prince Tunku Ismail Sultan Ibrahim, has claimed he was assaulted in police custody.

This was revealed by Parti Sosialis Malaysia (PSM) central committee member Khairul Nizam Abd Ghani, who visited the family in Tumpat, Kelantan.

However, Johor police chief Wan Ahmad Najmuddin told Malaysiakini he has not received any complaint regarding this matter, and therefore declined to comment.

Muhammad Amirul Azwan Mohd Shakri,19, was initially arrested in Kelantan and was later handed to the Johor police after spending two nights in a lock-up in Tumpat.

According to Khairul, the teenager's family claimed he was physically abused by Johor police personnel who came to Kelantan to transport him back to Johor to face the charge.

"Amirul complained he was beaten up, and that police personnel had 'pulled' his beard.

"They (Johor policemen) were angry as Amirul had insulted their prince," Khairul told Malaysiakini.

The PSM leader said Amirul's mother was distraught when he met her two days ago.

"She was crying and did not know what to do," he revealed, adding that PSM would engage lawyers to represent the family.

Khairul, who was also previously arrested with several PSM members with regard to social media postings critical of the Johor royalty, said a donation drive would be initiated to help the family.

Amirul was charged under Section 233 of the Communications and Multimedia Act 1998 for his Facebook postings.

Several people have been arrested for allegedly posting rude remarks against the crown prince, though Tunku Ismail had asked the police not to arrest his critics, but to arrange a meeting with him.

Various quarters, such as former law minister Zaid Ibrahim, have also asked the crown prince to intervene in Amirul’s case.