A 52-year-old man died in Chavakkad near Thrissur on late 6 July after allegedly being beaten up by a group of people when he questioned them for harassing his daughter.
Police said there was a minor scuffle between the man and the group, following which he fell unconscious and died at a hospital due to cardiac arrest.
The miscreants had allegedly made some remarks at his daughter who was sitting pillion on the bike with V Ramesh.
"There was a minor scuffle between Ramesh and the group on the issue. He suddenly suffered a heart attack and fell down unconscious," Chavakkad circle inspector AJ Johnson said.
"He was a heart patient and had been taking medicines for the last 19 years. The post-mortem report also said that coronary artery disease was the cause of the death," he said.
IPC 304 (punishment for culpable homicide not amounting to murder) had been slapped against the accused, who are now absconding.
A man hunt is on to nab the culprits and they will be arrested soon, the officer added.