In some instances, when illegal actions lead to someone's death, a criminal conviction may follow.
However, a criminal conviction is not necessary for surviving family members to win a civil wrongful death case against the party at fault for their loved one's death.
For instance, perhaps a doctor was negligent and the improper care led directly to the death of a loved one. It appears that the doctor's actions were illegal and perhaps even intentionally harmful.
However, due to a technicality, the doctor is not convicted of the criminal charges. Perhaps the police botched part of the investigation, for instance, and important evidence is not permissible in court. The doctor does not go to jail.
The standard of proof is lower in civil court, so you may still be able to seek compensation in a wrongful death case. Even if you can't prove it was a crime, you can show that the action led to someone else's death. That said, a criminal conviction can help surviving family members win their wrongful death case as it will serve as proof that the at-fault party's wrongful behavior caused the death.
Do not assume that the lack of a conviction bars you from seeking compensation. There are some high profile cases -- like the O.J. Simpson case, for instance, or the Michael Brown case -- where criminal convictions were never reached but wrongful death cases did result in financial awards or settlements.
As you can see, it is incredibly important to know the options you have to pursue a wrongful death claim after a loved one passes away. Be sure you know where you stand and what steps to take.