Phanurat said Montree may have fled to Chanthaburi, where he used to work and where he met his former wife Nittaya Nutadee, 32. Another possibility was Kanchanaburi, where he used to go hunting with friends.

Two more possible hideouts were the border town of Poi Pet, where he used to operate a business, and his hometown in Chiang Mai's Mae Ai district, he added.

Panurat said the police guarantee justice and security for Montree if he turns himself in, but if the police locate him and he resists arrest, officers may have to shoot to kill because Montree apparently has good gun skills and is a good marksman.

On Tuesday night Montree reportedly raided an electricalappliance shophouse behind Central Rama II department store and opened fire on his former sisterinlaw Siriphorn Nutadee and her husband Suchart after the two had just had dinner with three police officers. Siriphorn was later pronounced dead in hospital, while her husband was wounded slightly.

The gunman then ran after a car, in which the three policemen were driving away, and fired at the vehicle, prompting the three officers to get out and attempt to escape. Montree shot dead the driver, Pol Sr Sgt Major Banjong Katemanee, and Metropolitan Police Division 9 deputy commander Pol Colonel Praphon Klaekosol, 54, who was having an affair with Nittaya. Pol Lt Colonel Natthaphong Boolong was also shot and lay unconscious as Montree fled the scene in his car.

Although it is believed Montree's actions resulted from his jealousy over Nittaya's relationship with Praphon, after she continually refused his attempts to get back together with her, police were also looking into other possible motives for the shootings.