Dart Message and Professional Cleaner

His partner snorted angrily and lay down. He took another puff, raised his right hand, and stared at the burning cigarette. "If I'm unlucky, a bullet will get me before lung cancer does, and my wife and son will become someone else's…"

Swoosh!

A shadow suddenly spun its way through the gap in the window, cut through the burning cigarette, and pierced the tissue box on the dashboard.

Both of the FBI agents bent down at the same time as their gazes swept over their surroundings.

But the subsequent attacks that they were expecting didn't happen. It was utterly quiet.

Bent down, they looked at each other in bewilderment.

Eventually, the driver carefully picked up the tissue box and pulled out the item that was stuck in it… It turned out to be a dart.

Staring at the weirdly-shaped dart for a while, their expressions then changed as they exclaimed, "Batman?"