Not for merely erasing him from history, but to hide how he died, or some other reason?
Chihiro trying to make sure Khody isn't in "stasis" and alive, so left instructions to his minions?
Or evidence or something Schueler left IN the body like an implanted data device and mini holoprojector?
"I was killed by Chihiro he's a dirty rat!"
We know the archangels were all dead or gone when the strike happened and it was carried out by the "lesser angels", but who were they working for when they did it?
Chihiro or Schueler's last orders?