Judging from the nanny's clothing, the nanny is neatly dressed. And I judged that the time of death of the nanny should have been before six o'clock in the morning, which means that the nanny was killed before the old couple.

The nanny was also stabbed in the throat with a sharp weapon and died, but unlike the old couple, the nanny was stabbed 4 times in the neck.

This is supposed to be the nanny who is relatively younger, and after being stabbed in the neck, she was not killed immediately, so the murderous gangster made up for a few knives.

Lao Lu checked the room and said: "The lock of the door of the house is intact, which means that the murderer did not pry the door in, do you think the murderer will live with the nanny in this room before?" ”

I shook my head and said, "No." You can see that there are obvious drag marks on the ground from the door to the time when the nanny falls to the ground, which is left by the friction between the nanny's heel and the ground. I believe that the babysitter was controlled and assaulted by the killer when she heard someone knocking on the door. ”

Lao Lu nodded and agreed with my statement.

I continued: "Then it can be explained very well now why the murderer did not pry the door when he entered the villa, I think the nanny must have the key to the villa." The purpose of the murderer to kill the nanny in advance was to obtain the key to the villa. ”

So far, there have been three homicides at the villa site. Judging from the modus operandi of the crime and the wounds on the deceased's body, the perpetrator and the murder weapon were both a knife for one person. And this person is very familiar with the victim's home.

Based on this information, the police investigated people who were related to the victims, including some relatives and friends. The social relationship of the nanny was also investigated. At the end of the investigation, all suspicions were ruled out.

However, this does not completely rule out acquaintances from committing crimes. Because we have no way to thoroughly understand who the deceased had contact with, it is impossible to understand all the acquaintances of the deceased.

The villa was built on the outskirts of the city, and there was no surveillance here, so there was no way to obtain video footage of the murderer.

But because it is on the outskirts of the city, the interpersonal situation here is relatively simple, and most people who come and go in and out of this neighborhood are familiar with each other, so the police visited the surrounding villagers to see if they can learn some clues.

After the visit, I got an important clue.

Nearby villagers reported that in recent days, a man wearing a black peaked cap and long sleeves and trousers on such a hot day has often been in and out of the vicinity of the villa.

According to the investigation, the man wearing the cap was seen by seven villagers, but they all proved that the man was not a local.

And among the seven villagers, there is a young man in his twenties, because of curiosity, he once used his mobile phone to take pictures of the Cadillac SUV next to the villa. And in the few photos he took, in the upper left corner of one of them, you can faintly see the man wearing a black peaked cap.

The figure in the photograph is blurry, and the features of his face are not clear, but judging by his size, he is a strong man. This is consistent with the villagers' description, who said that he was a tall and strong man.

So could this man who was dressed strangely and deliberately concealed his facial features be the murderer? He frequently appears near the villa, is it just to rob and kill people? But so far, these are our speculations, and there is no valid evidence.

But this speculation is reasonable. A strong, tall man, wearing a cap and long sleeves on hot days, and not a local, was frequently seen around the villa. His series of strange behaviors cannot but make people suspicious.

So I decided to focus on such a person.

According to the villagers, the man in the cap came and went in and out of the villa at irregular times, sometimes in the early hours and sometimes in the afternoon. But it will come up often.

Then I analyzed, this man in the cap should have a fixed residence in this village, otherwise he would not have been able to appear nearby often in the near week.

However, after a survey of the village, it was found that the village was inhabited by permanent residents. However, this does not rule out the possibility that this person rented a house or lived in a guest house, because less than a 40-minute walk from the villa is a town.

The police investigated the hotel, guest house and tenants in the town and found no suspicious man wearing a peaked cap. Could it be that this man lives somewhere else, just comes here every day to step on something?

In the town, there is a surveillance probe, so Lao Lu mobilized all the surveillance videos in the town and searched for them in the surveillance video, and the target was the man wearing a peaked cap. But this search is tantamount to looking for a needle in a haystack.

When Lao Lu and they were scouting the surveillance video, I returned to the villa. Because I've always believed that by looking at the crime scene often, you can always find something that you didn't find before.

When I returned to the scene of the crime this time, I did make a new discovery.

I found an old building about 300 miles away from the villa. The exterior of the building is very old, and some of the walls have fallen off. I could see that in the five-story building, all the balconies looked bare, there were no flower pots, no clothes to dry, and no air conditioners on the walls.

Therefore, it was concluded that the building was an abandoned building.

I asked the villagers, who told me that this building was a dormitory building for the former mill, but after the mill closed down, the building was abandoned, and it is said that in these months, the government will come to demolish the building.

Abandoned buildings. So will this be a stronghold for murderers? If I'm a murderer and I'm spending a lot of time stomping, it's best to live close to the crime destination. And this abandoned building is the best choice.

So I strode into this building.

It was also outside the building that no one walked around in the mud that I saw clear shoe prints. And this kind of shoe print is more than one, on the same path, you can see a lot. It shows that people often come and go in this abandoned building.

This is a sneaker print, and the size of the shoe is 43, and by the length of the shoe print and the span of the stride, I surmised that the person who left the shoe print was a man who was about 183 cm tall.

This situation is consistent with the tall man in the cap that the villagers saw.

And can people who often go in and out of such abandoned buildings be serious people? So I know, I'm starting to get closer to the truth.

Following the footprints, I entered a unit of the abandoned building. After entering the corridor, you can smell a strong smell of dust and musty, which shows that this building has been abandoned for a long time.

When I entered the building, I rushed straight to the fifth floor. Why did I choose to go to the fifth floor? If I were the murderer, of course, I would have chosen the highest floor, so that not only could I have a good view of the situation downstairs, but also the upper floor would be more conducive to concealment.

When I came to the fifth floor, I saw that the door in the middle of the fifth floor was open. The two doors next to it are tightly closed.

This kind of door is an old wooden door, and that kind of door lock is also an old-fashioned lock that was often used in the seventies and eighties of the last century.

It can be seen that the wooden door in the middle was vigorously kicked open by someone's foot.

Walking through the door, there are two bedrooms and a kitchen and a bathroom. The room was filled with the smell of feces, which further indicated that this place had been inhabited not so long ago.

On the floor of the back room is a plastic sheet and some newspapers, and in the corner there are many bottles of mineral water and bags of biscuits and snacks. This is even more indicative of the fact that there were once people living here. And through the analysis of the spoilage of the residual food, the time of residence was just a few days ago.

And on the ground in the corner of the wall, there is a piece of dust on the ground that left traces of wiping, which were not intentionally wiped, but in this position, a bag was once placed. Therefore, it can be determined that the suspect has a bag, but it cannot be determined whether it is a shoulder bag or a backpack.

From the windows of this room, you can clearly see the villa, and if you have a telescope, you can even see every move in the villa.

So I concluded that this place was the stronghold of the murderer. And the man who was 183 cm tall and wore a peaked cap was the biggest suspect in this case.

I brought the mineral water bottles and food bags left by the suspect to the criminal investigation team.

Lao Lu watched me come back with this garbage, and asked puzzledly, "What are you doing here?" ”

I said, "I found the suspect's stronghold near the villa, and these things were left by the suspect. ”

Lao Lu immediately understood, and instructed the investigators to send the mineral water bottle to the forensic center to extract DNA, and at the same time to investigate where the mineral water and snacks were purchased.

The results of the investigation were not long in coming. The comparison of DNA is still inconclusive, but the place to buy mineral water and snacks is found.

Some of the snacks were purchased near the Wanzhou bus station, while the mineral water and another part of the snacks were purchased at the town supermarket near the villa.

From where these foods were purchased, I judged a possibility. The reason why the suspect bought snacks near the bus station is that the suspect is a foreigner, and those snacks were purchased when he arrived in Wanzhou. Moreover, the suspect came to Wanzhou for a purpose, and his target was the safe of the villa.

The snacks and mineral water bought at the supermarket near the villa are easy to explain, that is, the food he replenishes when he is squatting.

I said to Lao Lu: "These things have found a specific place to buy, as long as the suspects are found from the monitoring of these places, then the case can have a big progress." In my analysis, the suspect may not be able to be found at the station, because he should have been dressed relatively normally at that time, and even if we saw this person, we might not be able to recognize it. But in the monitoring of the town, we can recognize it more likely. The suspect may have been wearing long sleeves and trousers and a black cap. ”