The elderly couple died of severe burns when their house caught fire two years ago, and police said Sunday they have reopened the case after the victims' 42-year-old son said he was behind the blaze.

The man, only identified by police as Kim, was arrested last week for stabbing his wife and strangling his two-year-old daughter at his house in Okcheon, south of Seoul.

Okcheon police said his motives were still unclear, but the Yonhap news agency, quoting an unnamed officer, said he probably committed the crimes for money.

'Kim is accused of stabbing his wife to death after a marital quarrel. He also strangled his two-year-old daughter, who allegedly witnessed the murder of his wife,' the police officer told Yonhap.

Yonhap quoted police as saying Kim's wife had bought a new life insurance policy a month ago.

'He has confessed to killing his parents in 2006 to take possession of their real estate assets,' said the officer.

Kim was questioned at the time of the fire, but police concluded the deaths were suicide after he told officers his mother had suffered from severe back pain, Yonhap said. -- AFP