My cousin was mistakenly killed, what will the murderer be charged?

My cousin was a good clean guy. He and his wife were trying to better this guy who just turned 18 life. The guy was invovled with a gang that shot someone. That gang i guess came back for revenge. They were looking for the guy would lived with my cousin. My cousin was getting ready to leave his in laws house. he was standing outside the car with his wife filling out a paper and the guy who lived with my cousin was in the back seat when this guy shot four bullets, two injurying my cousin. He died on the way to the hospital. The shooter was looking for the guy in the back seat. He ran away and the police took the guy who lived with my cousin. i wanna know if they catch the shooter what penaty will he get??