Can anyone help me with this problem

academic query

in the market when gopalakrishna met rahul , out of anger and mental agony he caught rahul by his neck he was furious that his girl had left the house of rahul due to matrimonial disputes between them and once rahul had fight with gopolakrishna on this issue , this time gopala caught tighten the neck of rahul and slapped him and fell him down and tried to strangulate his neck and threaten him by shouted that today he will kill him , any how rahul had managed to escape from his grip and for his self defence he took a stick lying their and hit to the gopala out of afraid and to save his life as gopala is ready to kill him , the stick hitted on the stomach of gopala , gopala who was suffering from enlarged spleen died , here rahul has no intention to kill gopala because he was father in law of rahul , he hit him only for his self defence otherwise gopala kishna killed him , therefore he may be discharged from murder and may be released on the ground of self defenceu/s 100 of ipc.

plz send me reasonable fact/issues regarding the problem... Mala and Rahul were married in 2001 and were residing at Vijayanagar, Bangalore. However after few years their relationship got strained and were regularly quarrelling over frivolous issues. One Day, Mala left her matrimonial house with her eldest daughter Pinto and started living with her father Gopalakrishna at Jayanagar, Bangalore. Rahul kept his younger daughter, Pinkoo with his sister, Deepa and prevented Mala from seeing the child. During a noon Mala came to Deepa's house and forcefully took Pinkoo with her. Rahul on hearing this reached Gopal Krishna's house and quarreled. After two days of the incident, Rahul and Gopalkrishna happened to meet at a market place and started to quarrel and grappled with each other. Both fell down. In the heat of passion thus generated Gopalakrishna slapped Rahul saying he would kill him. Rahul in fit of rage took a stick lying nearby and gave a blow to the stomach of Gopalakrishna. Gopalakrishna who was suffering from diseased spleen fell down instantly. Before dying Gopalkrishna gave his Dying Declaration regarding the fight and the knowledge of Rahul about the enlarged spleen. Rajajinagar police arrested Rahul and filed charge sheet. Evidence was led by prosecution in the sessions Court and during trial an eyewitness stated that it was Gopalakrishna who slapped Rahul and started the fight. Trial Court relying on Dying Declaration of Gopalakrishna convicted Rahul for commission of murder and sentenced him for life imprisonment. Rahul challenged the conviction by filing a Criminal Appeal, before the High Court of Karnataka, relying on the deposition of the eyewitness. [ I am the counsel appearing for the State, what are the main poits that are supposed to be considered and how to prove that dying declaration is valid, i need supporting case laws]