If your loved one has been killed by the actions of another third party, then you may pursue wrongful death damages against the offending party. This is different from accusing the person of murder and prosecuting them so that they are punished for their actions. Here are the major differences between wrongful death and murder cases:
Type of Legal Action
A wrongful death action is a civil lawsuit that is handled in a civil court. This is much different from a murder case, which is a criminal lawsuit handled by a criminal court. Note that the civil suit of wrongful death can only be instigated by specific persons, usually close family members or those who had been financially dependent on the deceased. However, the government can instigate murder charges on its own; it doesn't need any relative of the deceased (or anyone else for that matter) to file the charges.
The Issue of Intent
Another difference is that murder is an intentional crime; for example, you cannot accuse a motorist of murdering your loved one because they disobeyed traffic lights. The motorist may still face other charges (both civil and criminal), but not just that of murder. You can only accuse someone of murdering your loved one if they committed the fatal act with the intention of killing the victim. This is different from the civil lawsuit of wrongful death where the intention of the perpetrator doesn't matter; whether the perpetrator intended to kill the victim or they were merely negligent, you can still charge them with wrongful death.
Another difference between the two cases is what happens if the defendant loses the case. In a murder case, the primary goal of the prosecution is to punish the defendant and protect the public from their murderous acts. The punishment takes different routes such as jail time and the death penalty. The defendant may also be ordered to pay restitution to the victim's family. In a wrongful death suit, however, the primary aim is to compensate the deceased family members' of the losses they have suffered as a result of their loved one's death. The defendant can still be punished, for example, by being ordered to pay punitive damages, but that is not the primary concern of the prosecution.
Level of Required Proof
Lastly, the burden of proof required in a murder case is vastly different from that required in a wrongful death case. In a murder case, the prosecution is required to prove beyond reasonable doubt that the defendant actually murdered the deceased. This makes sense because the states are so much high should the defendant be proven guilty. With a wrongful death case, the plaintive is only required to prove that it is more likely than not that the defendant is liable of the act.
For a wrongful death case, consult a personal injury lawyer, specifically a wrongful death lawyer.