How did Dong Er die in the Qin Dynasty?

It should be how Dong Er died in the TV series Dafuqin!

In order to save Fu Su from being killed by Lao Ai, Dong Er chased Princess Tung RH and Evonne was jailed. As far as Dafuqin is concerned, it wasn't Ai who killed Dong Er. The real murderer should be aimed at Reese, because Reese planned all the public plots at first, so Reese was the culprit. He wants to use Laoyi to implicate Evonne and Lv Buwei, so as to make Ying Zheng take charge. But Reese just thought about it and didn't give a complete response, because he also said: I didn't expect to shirk it.