A wrongful death lawsuit is a claim against a person or an entity that caused the death of another. This is a civil action, brought under the auspices of a state statute, and is usually brought by close relatives of the deceased victim. Wrongful death actions are also the only way to proceed when a company causes the death of another. For example, mining companies ill equipping their workers for underground disasters would be grounds for a wrongful death suit if employees died because of it.
When dealing with a wrongful death case, the standard of proof is usually a preponderance of evidence. In other words, there does not need to be a clear and convincing, beyond reasonable doubt kind of situation in the United States. It is different in other jurisdictions, like the UK and Australia, where their legal system requires a verdict on a balance of probabilities.
A wrongful death lawsuit is a tort action, as opposed to a criminal action. However, it should be noted that the two actions (tort/criminal) are not mutually exclusive, which means a defendant may be prosecuted in the criminal courts, but they may also be sued civilly in a wrongful death action. The most well known case to date that outlines both actions being brought, one criminally and one civilly, is the O. J. Simpson case.