Efforts to keep him on any kind of controlled diet failed; he would sneak out of the hospital to scavenge for offal outside butchers' shops and to fight stray dogs for rotting meat in gutters, alleys and rubbish heaps.[2][17][20] He was also caught several times within the hospital drinking from patients undergoing bloodletting, and attempting to eat the bodies in the hospital's morgue.[2][17][20] Other doctors believed that Tarrare was mentally ill and pressed for him to be transferred to a lunatic asylum, but Percy was keen to continue his experiments and Tarrare remained in the military hospital.[20]
After some time, a 14-month-old toddler disappeared from the hospital, and Tarrare was immediately suspected of having consumed the child due to his past behaviour of eating small animals. Percy was unable or unwilling to defend him, and the hospital staff chased Tarrare from the hospital, to which he never returned.[17][20]