The IPC 1860 was replaced by the BNS 2023 (in force 2024-07-01); no verified section mapping on file for Section 303 — confirm the corresponding provision (savings: Section 358, BNS 2023).
Whoever, being under sentence of imprisonment for life, commits murder, shall be punished with death. CLASSIFICATION OF OFFENCE Punishment--Death--Cognizable--Non-bailable--Triable by Court of Session--Non-compoundable.