According to the rights panel, M Jaishankar (38), who was undergoing imprisonment for 10 years, had committed suicide inside the jail by slitting his throat with a shaving blade on February 27.
"The commission has issued notice to the IG (Prisons), Karnataka calling for a detailed report in the matter within six weeks," the NHRC said in a statement.
The commission also noted that the state authorities have not informed it within 24 hours of the death, as per its guidelines, and hence has also sought an explanation from IG (Prisons) over not adhering to the guidelines.
According to the NHRC, inquiries have reportedly revealed that the convict was being treated for depression.
He was arrested after a massive manhunt in 2009, after raping and murdering a police constable in Tamil Nadu. Jaishankar escaped from judicial custody in 2013 by scaling the boundary wall of the prison, but he was rearrested. Since then, he was being kept in a separate cell, the NHRC said.