An unexpected answer

"The way you spend here is indeed different from ours," Zhao Yu said."Do you need to use a credit card to buy a tricycle?"

An hour later, in a quiet office, Zhao Yu was telling Li Zhenzhu and Masako Yangshan about his reasoning.

"The prices are too high," Li Zhen Zhu said."Tricycles are not cheap either! Also, there's a discount when using credit cards. "

"Here," Zhao Yu said, placing a piece of information in front of Li Zhenzhu."This photo is of the Han couple's fish stall. Do you see it?" They already had a tricycle!

"A tricycle should be enough for such a small fish stall, right? Why do you want to buy a new one?"

"So ..." Masako Yangshan said in surprise,"you discovered the problem? Did he use his credit card to buy a new tricycle? My God, what kind of brain do you have?"

"The point is," Zhao Yu said,"the timing of their purchase of the tricycle was too coincidental. It was right before Li Yiyan was killed!"