KUALA LUMPUR, Feb. 16 (Xinhua) -- Malaysian police have arrested a third suspect in its investigation in the death of Kim Jong Nam, the half-brother of Kim Jong Un, the top leader of the Democratic People's Republic of Korea (DPRK), a senior Malaysian police official said on Thursday.

Abdul Samah Mat, the police chief of Selangor state, told Xinhua that the suspect, a 26-year-old male Malaysian, was arrested in Ampang city of the state of Selangor.

The man is believed to be the boyfriend of the second suspect, a bearer of an Indonesian passport who was arrested on Thursday morning.

The police have been looking into the connections between the suspects and trying to pin down their roles in the death of Kim Jong Nam.

The police have been investigating as a murder case instead of sudden death of Kim and a local court has granted a seven-day remand order for the first two suspects.

The first female suspect, holding a Vietnamese passport, was arrested on Wednesday at the Kuala Lumpur International Airport's second terminal, where the deceased Kim looked for help after feeling unwell on Monday.

Kim died later on Monday enroute to hospital.

His body was taken to a hospital in Kuala Lumpur Wednesday for post mortem to ascertain the cause of his death.

The results of the post mortem are yet to be released.