Question: Lord Sri Krishna's Body
Why when Lord Krishna left this material world did He leave His body here?
Answer: Naturally It Remains Here
Krishna returned to the spiritual world in His original spiritual form. But since this entire material world is His virat-rupa, His so-called material body, naturally that form of His is left behind when He returns to the spiritual world.
In this connection my spiritual master, His Divine Grace A.C. Bhaktivedanta Swami Prabhupada, explains as follow in his purport to Srimad Bhagavatam, 1st Canto, Chapter 14, Text 8:
"It should be understood that when Lord Krishna was apparently killed by the bow and arrow of the hunter, the Lord left His so-called material body in the material world. The Lord is kaivalya, and for Him there is no difference between matter and spirit because everything is created from Him. Therefore His quitting one sort of body or accepting body does not mean that He is like the ordinary living being. All such activities are simultaneously one and different by His inconceivable potency."