One challenge could be understanding the scientific concepts involved. Time travel is a complex idea, and if they don't have a scientific background, it'll be hard for them to make sense of how the lab's time travel mechanism works.
They might face resistance from the people in the lab. The scientists could be trying to protect their research or hide certain aspects of it. Also, there could be some sort of time - related anomalies that mess with the cops' investigation. For example, evidence might disappear or change as time fluctuates. And they have to deal with the fact that the timeline might be constantly shifting, which makes it difficult to establish a clear sequence of events.
The cops may also have trouble getting cooperation from other agencies or departments. Since time travel is such an extraordinary concept, some might not take it seriously or might be too afraid to get involved. And if the time travel has affected different parts of the world or different timelines, the scope of their investigation could be huge, stretching across multiple dimensions or time periods, which is extremely challenging to manage.
The best chapter pointer here is Chapter 25, "He's Actually Mr. Shen's Son?!". It opens with Therefore, from his childhood, Jiang Shixu had felt an extreme aversion to... and closes on Having worked beside Shen Lan for over a decade, she had been there when....
The best chapter pointer here is Chapter 20, "Miss Su, your defense is somewhat clumsy". It opens with Several people turned their heads upon hearing the sound and saw three... and closes on So, he turned and questioned Jiang Li..
Chapter 878, "Do You Dare?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Su Yinwan not only chose a remote location for the meeting, but the...
Chapter 610, "Building a House?!", is the clearest early answer because it turns Shang Shuyue's situation into a concrete plot event.
A practical answer is Chapter 15, because it turns the idea into a concrete scene. The chapter opens with Jiang Shixu woke up from those nightmares filled with blood and darkness,..., adds pressure through Jiang Shixu's mind was starting to cloud, but for some reason, when he..., and ends on Since.
The best chapter pointer here is Chapter 20, "Miss Su, your defense is somewhat clumsy". It opens with Several people turned their heads upon hearing the sound and saw three... and closes on So, he turned and questioned Jiang Li..
Chapter 36 is the strongest chapter-level answer because it starts from But soon, people began to question the authenticity of Jiang Li's bare... and follows through on After swallowing the food in his mouth, he hurriedly took his megaphone....
Chapter 806, "Flip the Table!", is the clearest early answer because it turns Jiang Zhao Yuan's situation into a concrete plot event. Early on, Jiang Li looked at the dining room that seemed to have been hit by a.... By the end, In an instant, the dining room fell silent..
Chapter 825, "This method is absolutely not feasible!", is the clearest early answer because it turns Qixing Tower's situation into a concrete plot event. The chapter turns that into something concrete by moving from Beside him, Yu Qing: "....." Why does it feel like neither of them...
Look to Chapter 15 for the clearest answer. It begins with Jiang Shixu woke up from those nightmares filled with blood and darkness,..., keeps building through The two sleeping pills he took in the evening had left him with a..., and lands on Since she didn't move, Jiang Shixu also stayed put, and.