JMO his explanation is Tampering with Evidence/Corpse and also Accessory After the Fact/Murder. Didn't HPD say more charges might be coming?I was about to type the exact same thing.
He's admitted to helping hide a dead child.
The fact that they were concealing him, tells us he knew it was wrong even if having a dead child in his own apartment didn't seem to bother him personally.
Or, buying products with the sole purpose to conceal him, apparently also didn't bother him.
I can't think of a single logical reason his arrest hasn't already happened.