SHENYANG, Dec. 13 (Xinhua) -- Newly published archival files revealed that Japan started setting up police units illegally in Shenyang, capital of northeast China's Liaoning Province, as early as 1905, well before Japanese troops invaded northeast China in 1931.

Wang Ziyi with the Shenyang Municipal Archives said that in 1905 Japan began stationing troops along a local railway it had occupied, on the pretext of protecting the railway, and at the same time establishing illicit police units in and dispatching Japanese police to Shenyang.

As of Dec. 28, 1930, Japan had set up 14 such illicit police units, with 17 Japanese policemen stationed in Shenyang.

Japanese police played an important part in Japanese aggression against China, Wang said. "They gathered intelligence and infringed upon China's sovereignty, and they arrested and killed Chinese people."

Files showed that Japanese police spied on Chinese armies in 1928. In August 1931, Zhang Xuli, a Shenyang resident, was falsely accused of being bandit by the Japanese police and tortured to death.

Japan started invading northeast China on Sept. 18, 1931, when the Japanese Kwantung Army bombarded Shenyang under the excuse of explosions that occurred on the South Manchuria Railway.

Since the "Sept. 18 Incident," China waged a war against Japanese aggression for 14 years and finally won the first full victory against foreign invasion since the Opium War in 1840 at the cost of over 35 million military and civilian casualties.