Things that solve crimes

It is impossible to inspect the site inch by inch. The simplest example is to scan fingerprints.

When you want to scan a large area for fingerprints, you usually use an on-site inspection light. Just shine it and you can see a lot of fingerprints. It's simple and convenient.

It's just that this method is mainly used outdoors. The room is full of life traces of the deceased, and fingerprints are everywhere. It is also necessary to determine which fingerprints belong to the deceased.

The workload of hundreds of fingerprints is now crazy.

Therefore, it is more common for on-the-spot investigators to analyze the cause of the case and guess the direction of the case based on the scene conditions, and then conduct inspections where the criminal may have left traces.

Qin Henian followed him to the bathroom, and his breath suffocated when he looked at the movements of the two men. This technique was too rough.

Since the last case, he has understood that as a police officer, you must be versatile.

So, after the case was over, he started another course - on-site investigation.

After continuous efforts, the on-site investigation was promoted to level 4, and forensic pathology and forensic evidence science were also promoted to level 4 by him, which is really gratifying.

Unable to bear it any longer, Qin Henian took matters into his own hands. He took Fat Kancha's equipment, picked up the toothbrush cup on the sink, put a little water on a cotton swab, and wiped it gently.

Fat Kancha, who had his equipment taken away, was confused, what happened? Why did you rob him of his things?

Then he saw his team leader's actions and froze on the spot.

Generally, when people clean a cup, they use a cotton swab to wipe it along the rim of the cup. Sometimes this method can wipe the existing DNA, and sometimes it cannot.

Because it is just a simple approach, there are greater uncertainties and the results will be different.

However, their team leader's technique was different from theirs. It was a technique that Fatty rarely saw, or it could be said that his teacher had taught him a technique, but he didn't know how to do it.

Qin Henian first dipped the cotton swab in water and gently squeezed it with his hands until it was semi-dry.

When wiping, select a position at the mouth of the cup, rub the cotton swab up and down, and wipe it evenly three to four times to wipe out all possible DNA.

After wiping one spot, wipe it again after a period of time, and then wipe it again at a certain spot. Repeat this many times before the DNA extraction from a cup is completed.

This kind of wiping method naturally takes more time than wiping directly around the circle, but on the contrary, the probability of extracting DNA is also much higher.

This kind of wiping method is usually used by big guys. Fat Survey has never used this wiping method.

Although Fatty Surveyor doesn't know how to do it, it doesn't stop him from seeing it.

Cotton swabs are semi-dry and not wet. They are easier to transfer DNA than dry-rubbed cotton swabs or cotton swabs soaked in water. The wiping method at one point is also much more effective than wiping around a circle...

In terms of various details, Fat Xian confirmed that their team leader was a big shot.

Another young man, Xian Kan, was much smarter than Fat Xian Kan. He ran directly to help Qin Henian and stared at Qin Henian's movements. If he had the chance, he would be a fool not to learn from it.

Fat Xiankan muttered a few words in his mind, what a good boy, he is smart enough, so he ran over to help his team leader without thinking too much.

Sensing the gaze of young Xian Kan, Qin Henian slowed down his hand movements a bit. Hey, he can see as much as he can and learn as much as he can.

Understanding what the team leader meant, the young man became more energetic and looked at things more seriously than before.