Answer

Hemchandra Acharya was not killed by anyone. He is described as having lived a long life and then passed away naturally in Patan around 1172–1173 CE, at about 84 years of age. ( encyclopedia.com)

Explanation

Hemchandra, also known as Hemachandra Acharya, was a great Śvetāmbara Jain monk and scholar. The available sources describe his death as a normal passing, not as an हत्या or murder. ( encyclopedia.com)

Takeaway

So the correct answer is: no one killed Hemchandra Acharya. He died naturally after a distinguished life of Jain scholarship and spiritual service. ( encyclopedia.com)