Sounds like Lon Horiuchi was on the team...
Remember him..FBI sharpshooter who killed Randy Weaver's dog, then his wife.
All too familiar.
And his son, Sam.
Also back-shot.
The dog got shot by the sheriff. The 13 year old son then nailed the sheriff. A marshall then shot the kid. The older stepson escaped back to the home. Everything went downhill from that point on.
Horiuchi was called in to use his sniping skills to shoot the stepson, Randi, his wife and the baby I presume. He did lay another round into the stepson and killed the wife through a closed door.
The fellows who planned this one got promoted.