Why did Sung River kill Yan Poxi?

When she went to Yuncheng County in Jeju with her parents, her father died of illness and there was no money to bury him. Song Jiang gave alms to the coffin and gave her twelve taels of silver. Her mother thanked her and sent her to Song Jiang's outer room.

Because Song Jiang doesn't care about women, Yan Poxi hates him. As a result, Yan Poxi fell in love with Zhang Wenyuan, who was also an escort, and hooked up with him. Later, Yan Poxi happened to get the classic letters and rewards for Song Jiang, and Yan Poxi threatened her to go to court. Sung river killed her after asking many questions that night. Since then, in order to avoid lawsuits, Song Jiang has taken refuge in Chai Jin, a small whirlwind.

Extended data:

Song Jiang was originally an escort in Yuncheng County, Shandong Province. Yan Poxi discovered his communication with classical music, so he angered Yan Poxi and fled home to hide. Later, he went to Qingfeng Village to take refuge in Huarong Road, but when he was watching lanterns in Qingfeng Village, he was framed and imprisoned by Liu Gao's wife in Zhizhai. On the way to Qingzhou, he was rescued by Yan Shun and others. On the way to Liangshan, I learned that my father had passed away, but I was caught on my way home to attend the funeral and sent to Jiangzhou.

He was sentenced to death in Xunyanglou, Jiangzhou, but was rescued by Liangshan army on the day of execution and defected to Liangshan. After the attack on Classical City was shot in the head, Song Jiangba won the first prize, followed by two wins in Tong Guan and three wins in Gao Qiu. After accepting the harness, he led the Liangshan army to attack the Liao State and pacify Fang La. After being sealed by the imperial court, he was framed by Cai Jing, Tong Guan and Gao Qiu, poisoned and buried in Liaoerwa.