COLOMBO, March 29 (Xinhua) -- Sri Lankan police on Thursday arrested the island country's prison's chief Emil Ranjan Lamahewa over a massacre of 27 inmates during a prison riot in 2012.

Lamahewa was arrested by the Criminal Investigations Department from his residence in capital Colombo, Police Spokesperson Ruwan Gunasekara said.

On Wednesday, another inspector attached to the Police Narcotics Bureau was also arrested over the prison riot.

The riot at the highly guarded Welikada Prison in capital Colombo broke out on Nov. 9, 2012 during a search for illegal arms within the prison premises.

The riot left 27 inmates dead and 40 injured.

The Sri Lankan government led by President Maithripala Sirisena had appointed a committee to investigate the riot and a report was compiled on the incident.

The 2012 massacre was the worst prison violence in the country since 50 inmates were hacked to death in a 1983 riot.