Tokyo ? A man claiming to have fatally stabbed a former Japanese health official in a high-profile case that police believe is linked to the loss of millions of pension records turned himself in to authorities, police said Saturday.

The 46-year-old man told police that he had killed the retired vice health minister, who was found dead along with his wife Tuesday at their home outside Tokyo. Police initially said the man confessed to attacking the couple.

Police arrested the man on a knife possession charge after finding a bloodstained knife in the back of his car, a police spokesman said on condition of anonymity, citing department policy. It was not immediately clear why the man was not arrested in the killing.

Investigators were questioning him in connection with the couple’s stabbing and an attack on the wife of another retired bureaucrat earlier this week, a metropolitan police official said on condition of anonymity, also citing department policy.

Police have suspected the attacks were connected to the ministry’s mishandling of millions of pension records — a debacle that has drawn intense ire from the public, many of whom lost their retirement funds as a result.

The two officials were retired vice health ministers who were key figures in setting up the pension system 20 years ago.

Kyodo News agency however reported that the man told police that he killed the official because of his anger over the death of his pet, for which he held a health official responsible. Kyodo said police also found blood-smeared sneakers, gloves and cardboard boxes in the man’s car.

Takehiko Yamaguchi, 66, and his wife were found dead Tuesday near the doorway of their home just outside Tokyo.