A 67-year-old undertrial died of cancer at the Mandya Institute of Medical Sciences (MIMS) hospital here on Wednesday. Mandya sub-jail officials identified the deceased as Mahadeva alias Kencha Mahadeva, a native of Garibi Site near Kere Megala Doddi in Maddur taluk. The deceased, accused in six theft and burglary cases, had been in the prison since August 19, 2011. He had been suffering from cancer and the prison officials had admitted him to MIMS hospital on Monday. Sub-jail superintendent M. Sunder has filed a case of unnatural death at the Mandya West police station.