Zhou Ning took a deep breath and, pointing to the smear marks on the window, said:
"This handprint looks like it was left by a little boy. It should be tested against the baby bottle in the living room. Fingerprint, substance, DNA—it's likely left by the boy.
If you say that the parapet in the living room and the windowsill could barely support two kids climbing up, this mark is 1.2 meters above the windowsill. The two children couldn't have reached it without assistance, which is why I suspect the boy didn't fall accidentally."
Liu Yufei didn't seem too surprised, just clenched her teeth tightly and swung her fist after a long silence.
"I'll go downstairs and inquire with the child's father, then check the surveillance of this unit's elevator to see if anyone other than the old lady and Zhang Bo has come in or out. Even a tiger doesn't eat its cubs; surely it can't be Zhang Bo who did it?"