There is a lot of evidence to prove that:
1 I lost the ID of the garden, but I finally found it. Kidd stole it. The paint on the ID card is evidence.
At first, the customer told Kogoro that he was the fifth detective to be entrusted, and one was investigation, referring to Hattori, without a white horse.
The client's name is Hattori, not White Horse.
When Conan Hattori and Baima are together, there are only two bright spots on the client computer, indicating that Baima's ID is normal.
Conan finally said that Kidd had been with them.
The white horse stole Hattori's mobile phone in the dark.
The heights of Kidd and Hattori are 174 cm, and the height of White Horse is 180 cm. From the picture, the white horse is as tall as Kidd.
To sum up, the white horse is installed by Kidd.
I found this, and maybe there's some evidence I didn't find.