Police arrested a man for torturing and murdering a woman he met on a dating app - and rescued another brutally-beaten woman from his room.

Police rescued the woman after entering the apartment in Phatthalung on Wednesday night to arrest Thanadej Kaewchuang.

Her body was bruised, her face was swollen and 10 ribs were broken.

Thanadej, 27, was wanted by police on an arrest warrant issued on Sept 29 for killing and torturing Kamolphet Lamul, 26, in Bangkok on July 21.

Thanadej met the woman on an online dating app, and then persuaded her to move in with him. She was locked in for about one month and beaten until she died. He then went on the run.

Police received a tip-off that he was living with another woman, identified as Ms Noei, in an apartment in Muang district of Phatthalung.

Ms Noei, who lived in Lamphun, told police that she met Mr Thanadej on a dating app in early August. One month later, she decided to take a train to the southern province after he told her that he was falling in love with her and wanted to meet up.

Mr Thanadej picked her up at Phatthalung train station for breakfast. He then took her to his apartment and went on a jealous tirade, accusing her of looking at another man during the meal.

Ms Noei said she was locked in the room for more than a month and was continually beaten until the police showed up.

"When he took meth pills, he attacked me more," she said. "I was suffering in the room."

Urine tests carried out after the arrest showed Mr Thanadej had taken drugs.

Police said the man had confessed both to the murder charges in Bangkok and attacking Ms Noei in Phatthalung.