HONG KONG — The police in Malaysia said on Monday that they had found mass graves on the country’s border with Thailand that may hold the remains of migrants who died in camps run by smugglers.

Inspector General Khalid Abu Bakar of the Malaysian police said that more than 139 graves were discovered, some with more than one body, in an investigation that began May 11. The graves were found in 28 camps in the state of Perlis, in Malaysia’s far north.