Thung Thong Police Lt Sawanya Eidthrong said that Nopparit Sophapan allegedly assaulted his grandmother, Jintana Chairab, at her home in Moo 7 at 3am.
She later died at Vachira Phuket Hospital.
“More than 20 officers are looking for him right now,” Lt Sawanya said.
“When help arrived, the victim was still alive but she was badly injured. Kusoldharm rescue workers rushed her to hospital, where she died at 7:45am.
“Local residents told us that Nopparit was intoxicated when he attacked her and fled the scene on a motorbike,” he added.
Lt Sawanya urged people to report any possible sightings of Nopparit to the nearest police station, or directly to Thung Thong Police Station at 076-321321.
Nopparit has a history of violence, Lt Sawanya added.
“The suspect was arrested before when he assaulted his wife near a 7-Eleven at Thung Thong,” he said.