Dou Chengfeng bit down hard on the inside story, unwilling to speak, and it wouldn't be appropriate to use torture. Although he was just a concubine's son of the Dou Family, Xiao Song himself was from a noble family and was very familiar with large clan affairs. Even a neglected concubine's son couldn't be easily controlled. In this case, Dou Chengfeng appeared to be just a victim, with no evidence of him committing the crime; they could only confine him to the Dou Family's separate residence.
For Xiao Song, it would have been easier if Dou Chengfeng were dead. Sometimes what people want isn't the truth, but a result. Even if someone could see that this result wasn't the actual truth, as long as it suited their wishes, they might even accept it more readily than the truth.
Xiao Song was never one to chase the truth zealously in solving cases, and sometimes, even when he was well aware of the facts, he would conceal them for various reasons.
