The fire at Zhao Hanlin's house back then might not have been just an accident. It was very likely that someone plotted a murder for money.
According to the old lady's description, it wasn't difficult to know that people in the village would know Zhao Hanlin's whereabouts as long as they paid attention.
The day before the fire, Qi Anyan took her one-year-old son back to her own family. This shouldn't be a secret. People would know after asking around casually.
And Zhao Hanlin was also in town for business that day. It was possible that he would be gone for a few days, so there was no one home at Zhao Hanlin's house and it was naturally convenient for a thief to commit a crime.
Before that thief committed the crime, he must have gotten the information of the whereabouts of Zhao Hanlin's family.