In response to the increased Japanese activity in the Kando region, An Joong-Gun led his guerilla army on a raid there in June 1909. The raid was a success, resulting in many Japanese deaths. Despite such guerilla activities, the Japanese finally arrived at an agreement with the Chinese. The treaty, signed on September 4, 1909, allowed the Japanese to build a branch line to the Southern Manchurian Railway to exploit the rich mineral resources in Manchuria. In return, the Japanese turned over to the Chinese the territorial rights to Kando. This brazen act of selling Korean territory to another country was the last straw for many loyal Koreans such as An Joong-Gun. He set out for his base of operations in Vladivostok, Siberia, to prepare for his assassination of Hirobumi Ito.
Russia was becoming very nervous at the level of Japanese activity in the northern Korean area and Japan's obvious designs on Manchuria. Ito, who had officially become the president of the Japanese Senate (an aristocratic government body), arranged to meet with Russian representatives at Harbin, Manchuria, to calm their fears over the Japanese intentions to annex Manchuria and invade China. The final plans for the meeting between Ito and General Kokotseff, a minister-level Russian govermner1t official were set for October 26, 1909.
When Ito arrived at the Harbin train station at 9:00 a.m. on October 26, 1909, An Joong-Gun was waiting for him. Knowing full well that he would never escape alive, and that torture awaited him if captured by the Japanese, An Joong-Gun shot Ito after he stepped off the train. Following the assassination, Joong-Gun was captured by Japanese troops and imprisoned at Port Arthur. While in Japanese prisons, he suffered through five months of extremely barbarous torture. Despite this unbelievable treatment, it is said that his spirit never broke. On March 26, l9l0, at 10:00 a.m., Joong-Gun was executed at Lui-Shung prison.