That question is nonsensical: 1. The jury never has to justify anything; 2. “Murder” is a legislated concept. The jury is not beholden to the legislature, and is free to reject the laws they create.
Where the jury feels that enforcing the legislated law would be an injustice, they are free to rule “not guilty”, even if they believe the accused’s actions violate that law.
That question is nonsensical: 1. The jury never has to justify anything; 2. “Murder” is a legislated concept. The jury is not beholden to the legislature, and is free to reject the laws they create.
Where the jury feels that enforcing the legislated law would be an injustice, they are free to rule “not guilty”, even if they believe the accused’s actions violate that law.