Not exactly.
It's more like a 'felony murder' charge. That's where anyone participating in a crime is criminally liable for any death that may occur during the commission of the crime.
These sorts of laws were put in place to hold the 'fringe' actors (lookouts, getaway drivers, ect) responsible for any death, even if they weren't in the room when the death occurred.
Similarly, if someone starts a fight, and someone dies during the fight, the person who instigated it is often arrested & charged, even if it wasn't their actions that caused the death.
I'd like to hear why the Grand Jury declined to indict the accused shooter.
I haven't found any specific reason, but some of the stories mention the fact that the pregnant woman attacked the shooter, and that the shooter's actions were self defense.
If so, the shooter shouldn't be off the hook for the fetus. Self defense doesn't work that way. If someone shoots in (legitimate) self defense, but accidentally strikes a bystander, the normal result is the 'self defense' shooter being charged (negligent homicide or negligent use of a weapon).