The national police chief has ordered a manhunt for a key suspect wanted in connection with the murder of millionaire Wannee Jiracharoenying, 58, whose body was found in a refrigerator at a house in Chiang Mai on Sunday.

The manhunt started after an arrest warrant was issued on Tuesday for Withun Sitabut, 39, from Lampang, who is now wanted on charges of robbery resulting in the death of Wannee.

The police chief had instructed that all possible investigation techniques be used to track down the suspect. Police say he first met the victim when he took her and a group of Buddhist nuns to a temple, and they later became friends.

A BMW car owned by Wannee and allegedly stolen by Mr Withun had been found abandoned in a wooded area in Chiang Mai’s Saraphi district and seized for inspection. 

In another development, a woman said to be a girlfriend of Mr Withun was detained at Chiang Mai airport for questioning, said a source.

Identified only as Nam, the woman was detained after a trip to Koh Samet with Mr Withun.

She told police Mr Withun paid for her trip, both the return flight from Chiang Mai to Bangkok and a car rental to take them from Bangkok to Koh Samet, where they checked into a luxury resort and went on a spending spree.

At the end of the trip, Mr Withun saw her off at Don Mueang airport before she boarded a plane back to Chiang Mai, said the source.