News program about the death of Kim Jong Nam, the older half-brother of the DPRK leader and the eldest son of late leader Kim Jong Il, is seen on TV at the Railway Station in Seoul, South Korea, Feb. 14, 2017. (Xinhua/Yao Qilin)

KUALA LUMPUR, March 31 (Xinhua) -- Malaysia on Friday called on the Democratic People's Republic of Korea (DPRK) to hand over four suspects in connection with the death of a DPRK man last month at the Kuala Lumpur airport.

Malaysia's Deputy Prime Minister Ahmad Zahid Hamidi had said earlier this month that the DPRK man had been confirmed as Kim Jong Nam, based on the DNA sample obtained from his child.

On Friday, Malaysian police chief Khalid Abu Bakar told reporters that a criminal investigation into the case of the DPRK man's death is still ongoing even after both sides freed each other's nationals.

Khalid made the remarks while attending an event here. He said the criminal investigation was not compromised by negotiations between the governments of Malaysia and DPRK.

Malaysian police had previously said two female suspects, one Indonesian and one Vietnamese, together with four DPRK suspects, carried out the Feb. 13 attack on the DPRK man at the airport.

Khalid said the police could wait "for years" for the DPRK to hand over the suspects, who are also wanted by the Interpol which has issued a red notice on them.

On Friday morning, a plane piloted by several Malaysian air force pilots brought back the nine Malaysian citizens who had been stranded in DPRK to Kuala Lumpur International Airport.