Easy. Wronful death can be anything that causes death unintentionally too. It is not a requirement to show and prove motive and intent of the defendant. There is no death penalty statue for wrongful death in this country, also.
To convict one of murder, the prosecution mush be able to prove motive, intent, and action of the defendant causing the death. This is mostly done with the medical examiner and/or coroner's Cause of Death Report corroborated by the police evidence linking the defendant to this action- all the while showing his motive and intent to cause the death of the victim
You could get in a vehicle accident today, and accidentally kill someone. It happens daily in America. You possibly can be charged with vehicular homicide; depending on the evidence. (DUI for example) You could face a civil trial for wrongful death and possibly sued for monetary damages.
However, you would never be charged with murder in a traffic accident; even though someone unfortunately died.