Situ Wenwen is indeed very delicate, wearing a simple and elegant skirt, much like a blooming lily.

"Situ, I want to ask, what did you do during this 15-minute break?" Wu Tongguang asked.

"I was originally sorting out the notes from today's lecture, and I did some calculations and wanted Professor Zhu to review them for me."

"What's your question?"

Situ Wenwen took out a notebook, which was full of mechanical formulas, and the notes she made were very careful and careful, and it could be seen that this was a very diligent and inquisitive student.

Wu Tongguang asked again: "Professor Zhu saw this, what did he say?" ”

"Professor Zhu seemed to be in a hurry, saying that he asked me to put it away first, and when the next class is over, he will specially tutor me in this calculation."

Wu Tongguang asked curiously, "In a hurry?" ”

"Yes, when I chased it out to ask a question, I guess half of the break was over. Professor Zhu should have something else. ”

"You were talking to Professor Zhu outside the lounge door?"

Situ Wenwen replied, "Yes." ”

"Did you notice anything unusual in the break room?" Wu Tongguang asked.

Situ Wenwen thought for a while: "No......"

"'No,' you mean you're not sure yet, are you?"

"Yes, so to speak."

Wu Tongguang asked again, "Is the door open or closed?" ”

Situ Wenwen replied: "The door is open, but I don't see inside, Professor Zhu is blocking the door." ”

"Are you sure?"

"Sure, very sure."

Wu Tongguang asked again: "What about after that?" ”

"And after that?"

"After that, I'll be back after that."

"Are you back in the classroom?"

Situ Wenwen said: "No, I walked to the door of the classroom and heard Bai Wenyu and the others talking..... Say something rude, and I'll go out......"

"Where did you go in the next few minutes?"

"I'll go downstairs."

"You're alone?"

"Yes."

Wu Tongguang finished asking, and roughly sorted out his thoughts, the whole break between classes lasted for 15 minutes, Wang Nianru was the first person to contact Professor Zhu after class, he told Professor Zhu that there were guests visiting, and then Professor Zhu went directly to the lounge.

There were three students in front and behind who occupied half of his time, and during this half time, Professor Zhu walked from the far left end of the corridor to the far right end of the lounge. The three students talked with Professor Zhu at the door of the classroom, the staircase, and the door of the lounge.

When Wu Tongguang and the others arrived at the door of the lounge, they found that the lounge was closed, and there was nothing abnormal inside, so they waited outside for a while and called Secretary Wang, which was about 2 minutes, that is, Professor Zhu entered the lounge, and it was only 3 to 5 minutes after Wu Tongguang and the others came to the door of the lounge, and his death happened in these few minutes.

If it is said that he killed, what kind of murderer can kill an adult in the prime of life silently and quickly in this closed lounge?

If it was suicide, then why did he commit suicide?

Wu Tongguang thought in his heart: "If he killed, what was the murderer's motive?" Could the murderer be Zhuo Shaoqing, who went and returned, because of some major interests, what happened to Professor Zhu, and then killed Professor Zhu? The three students, except for Bai Wenyu, the other two, Xu Zhihan and Situ Wenwen, did not have a complete alibi, especially that Situ Wenwen, after talking with Professor Zhu, she went downstairs alone, and she didn't know what to do......"

"What is teaching secretary Wang Nianru doing these 15 minutes?" Li Wutong asked.

Wu Tongguang said: "I have already asked, and he told Professor Zhu that we have been in the teaching office since we visited. ”

"Can anyone prove it?"

"He's the only one in the senator's room."

"That means he doesn't have an alibi either." Li Wutong said.

"But he cites another thing to prove his innocence." Wu Tongguang said.

"What?"

"His office is downstairs, and it's too late." Wu Tongguang said.

Li Wutong said: "What does it mean that time is too late?" ”

Wu Tongguang said: "His academic office is on the first floor, and Professor Zhu's class today is on the third floor, his academic office is directly below the lounge, after he informed Professor Zhu of a visitor, he walked down the stairs and returned to his academic office, until we couldn't open the door to rest, and the security guard called him to come, he ran up again." ”

"What's wrong with that? Can it explain anything? ”

Wu Tongguang analyzed: "There was only a 15-minute break, Professor Zhu answered questions for students for almost half of the time, he went to the door of the lounge, that is, the remaining half of the time, before that, the three students did not see Secretary Wang, indicating that Secretary Wang had indeed gone downstairs to go back." ”

"After we arrived at the door of the lounge, we waited for a while, and the guard called Secretary Wang, who ran from downstairs to the rest door for about 2 minutes. If he was the murderer, he would have to run up from downstairs after Situ Wenwen left, kill Professor Zhu, and then run back downstairs until the guard called him, and he shouted again, which took at least 6 minutes to go up and down the stairs on three sides alone, and Professor Zhu entered the lounge and died within seven to eight minutes, leaving him with enough time to commit the crime. ”

Li Wutong said: "What you said makes sense, but it is also possible that he didn't return to the teaching room on the first floor at all, just waited on the second floor, and waited for the opportunity to hear Situ Wenwen leave, so he ran up, which saved a lot of time." ”

Wu Tongguang frowned and said, "I also thought about this possibility, but when we came up from the first floor, we didn't see him at all, and we didn't meet him!" ”

"Maybe he's hiding in that corner and we haven't found him at all?"

"We didn't find him, of course it's possible, but don't we hear the sound of walking up the stairs?"

The two fell into deep thought, Wu Tongguang said: "We should take a closer look at the scene, I think, if he kills, there will definitely be suspicions, but we didn't find it." ”

"Tongguang, if you look at the scene again, but you have to promise me, this is the last time we will see the scene, if there is no gain, we will leave here quickly."

"If you waste any more time here, if Xiao Guodong and they bring people over to surround this place, it will be troublesome. It's been a day and a night since Lei Yin's death, and the more time passes, the harder it is to know the information he wants to pass on to us. Li Wutong said.

Wu Tongguang said: "I understand, let's watch the scene again one last time. ”