KUALA LUMPUR—Four North Korean suspects in the killing of North Korean leader Kim Jong Un’s older half brother left the country on the day of the incident, Malaysia police said on Sunday.

The police will seek help from Interpol to locate the North Koreans, none of whom carried diplomatic passports, Malaysia’s Deputy Inspector-General of Police Noor Rashid Ibrahim said at a news conference. Police are also looking for three other suspects in the case, he said.

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