He knelt by the body, pressing his slit palm to the slain boy's forehead and leaving a smear of blood that mixed with the dirt on the child's dusty face.
"Novice Frael," Vayne consulted his narthecium, tapping at the keypad as he examined the readout. "Age thirteen, initial stages of implantation."
"There's very little decay," Argo observed in a soft voice.
"No. Blood and tissue samples indicate he died three or four days ago. My guess would be the day before we arrived."
...
"If he'd been fully human," Vayne said, "he'd have died in the first two weeks. Thirst. Starvation. Trauma. It was a miracle his initial implantations even allowed him to survive this long. Almost sixteen weeks, Argo. That's worthy of the rolls of honour itself."

Heroes of the Space Marines pgs. 401 and 402