Bahrain authorities have launched an investigation into the death of a 20-year-old prison fugitive, whose body was found in Malkhiya village early Saturday.

Hussain Mahdi Ibrahim, the inmate, died under mysterious circumstances, while the Interior Ministry alleged he had been attacked by some unknown assailants.

The ministry said it received a call from the hospital of Salmaniya Medical Complex and was informed of a deceased person brought in.

Several radical opposition groups claimed on social media that the fugitive was among a group of six men, who had been tried in May and then put into custody.

Some men armed ambushed a police vehicle that was transferring them and set them free.

The inmates were allegedly among a mob of 120 people who attacked Sitra police station in August 2012.