Thai police on Wednesday arrested a suspected serial killer that allegedly killed five women working in the sex trade around the country.

Somkid Pumpuang, who used several other aliases, was arrested at his current girlfriend's house in a northeastern province some 342 kilometers away from Bangkok.

He had been wanted by the police for allegedly murdering five sex workers around the country since the beginning of June.

Somkid admitted having killed four women after having sex with them, for they demanded more service fee. But he denied the fifth killing of a woman in southern Thailand.

"He appears cognizant, but we need the advice of the experts," Crime Suppression Division Commander Maj-General Winai Thongsong was quoted by newspaper Nation as saying on Thursday.

Police have expressed doubts about Somkid's motives and would be using psychiatrists to help with their investigations.

Besides murder, Somkid also faces numerous charges of theft, and is in detention pending an investigation and assessment of his psychological state.

Source: Xinhua