In the case of Ms Lai's disappearance in Hangzhou, why didn't the police ask her husband Xu through a polygraph?

In the case of Ms Lai's disappearance in Hangzhou, why didn't the police ask her husband Xu through a polygraph?

1 Xu didn't behave like the suspect at first, the police didn't suspect Xu because Xu said his wife disappeared in the early hours of the morning. At that time, Xu told a lot of big lies, the main purpose of which was to take a partial rhythm and let the police think that his wife had run away from home.

After his wife disappeared, it was Xu who called the police. He planned it? The thief shouted to catch the thief? At first, it was difficult to determine the location of the scene. He is the murderer.

At that time, Xu didn't act like a suspect at all. He created a series of illusions to make people think that his wife did not die of murder, but ran away from home. According to Xu at that time, there was only one pajamas missing at home. It can be seen that Xu wanted to frame his wife because he had a private meeting with others and chose to run away from home.

At this stage, the police did not focus on Xu at all when they were not sure whether he was killed, so there was no need to use a polygraph on him.

2. People's suspicion of Xu Can cannot be used as a criterion for conviction. With the progress of the case, the real situation of the case has gradually surfaced.

Although many people suspect that Xu's wife came to see the young lady and that Xu killed her, there is no evidence. Even as expected at first, there is no evidence to convict people.

If there is no evidence, it will undoubtedly be strongly opposed by Xu if he uses the polygraph only out of suspicion. And this kind of opposition is protected by law. Assuming that Xu is really not the wife killer, it is undoubtedly an absurd decision to use a polygraph on him.

Without any evidence, using a polygraph on him is like interrogating a child who is not lying, which is why the police didn't use a polygraph on him at that time.

When the truth comes out, there is no need to use polygraph. With the further development of the incident, when the truth gradually surfaced, there was no need for the police to use a polygraph.

At that time, although Xu told many lies and succeeded in attracting the attention of the police to other places, the police were obviously much smarter. In other words, Xu seriously underestimated the police's ability to solve crimes. In the meantime, the police may have predicted that Xu might be the murderer earlier than our public guess, but because there is no evidence, they have to continue looking for evidence.

After the police obtained strong evidence, they directly arrested Xu, and the matter was put on the table at once. At this point, Xu has no excuse to deny and excuse. At this point, Xu directly admitted to killing his wife, and it was unnecessary for the police to use a polygraph.

The above is my understanding. In the case of the disappearance of Ms. Lai in Hangzhou, the police did not ask her husband Xu through a polygraph.