This is very simple, Ouyang Ping wants to dig out a little valuable content from Gui Qingguan's mouth, the salaries of the teachers of Duolun Road Primary School are all taken from the Industrial and Commercial Bank of Qili Street, when Teacher Ma withdraws money, are there any other teachers who will take the money? Since Gui Qingguan knew Teacher Ma, he should know other teachers.

"Gui Qingguan, yesterday afternoon, in addition to Teacher Ma, did you see other teachers from Duolun Road Primary School?"

"No—no, at least at counter three, I didn't see the teacher at Duolun Road Elementary School."

"You have a good memory."

"Comrade policeman, have you ever asked Mr. Ma? It stands to reason that he was queuing up in the business hall, and if there were other teachers, Mr. Ma should be able to see that I was inside the counter, and under normal circumstances, I would not pay attention to the situation in the hall - we would only notice the customers who came to our counter to do business. ”

What Gui Qingguan said is also the truth.

The investigation of Ouyang Ping and his entourage came to an abrupt end here at Gui Qingguan.

After that, Ouyang Ping and the others had two more contacts with Mr. Ma and Chen Hongxiang, but none of them could provide more information.

Since the case, Chen Hongxiang and his wife have rented a house in the community, and their three relatives have lost their lives in Building 206, Building 5, and it is difficult for Mr. Ma to live in this house anymore, and even Chen Hongxiang and his wife do not want to go back there.

Ouyang Ping had to make some adjustments to the survey, because of the time relationship, the initial survey visit was limited to Mr. Ma's unit, and in the case of no results, Ouyang Ping expanded the scope of the survey visit to one unit; Originally, the investigation and visit to Building No. 6 was limited to the businesses on the first floor, but Ouyang Ping expanded the survey to all the residents above Building No. 6, and Ouyang Ping also conducted an investigation and visit to the residents of Building No. 4. Building 4 is in front of Building 5. We all know that before the 90s of the 20th century, buildings were generally five-storey, and the distance between buildings was relatively narrow, and the residents of Buildings 6 and 4 were likely to see Mr. Ma's house if anyone was at home.

After on-the-spot investigation, standing on the balcony of some houses in Building 6, you can see the kitchen and the inside of the two rooms of Mr. Ma's house (Chen Qiming and Chen Qidi's room); Standing in the kitchen and north-facing rooms of some houses in Building 4, you can see the situation on the balcony of Mr. Ma's house and the inside of the master bedroom (Mr. Liu was killed in the master bedroom).

Building 206 of Building 4 has been home for a long time, and on the afternoon of the 12th, there are three people at home of Building 206 of Building 4. These three people are the head of the household, Zong Youzhi's wife, and the thirty-five-year-old daughter Zong Guimin, who is paralyzed in bed.

In order to let their daughter see the scenery outside the window, the old couple made their daughter's bed in front of the window, and Zong Guimin sat on the bed to see the balcony and master bedroom of Teacher Ma's house.

Unfortunately, on the afternoon of the 12th, Zong Guimin didn't see anything. Because Mr. Ma's master bedroom and balcony have curtains, and Mr. Liu likes to pull curtains, even in broad daylight, he also draws the curtains, there are curtains to cover, and he can see people at night, but he can't see anything during the day. What's more, the curtains of Mr. Ma's house are very particular and are double-layered. It is precisely because of the curtain that the murderer will carry out the murderous plan with impunity.