Jack did not murder everyone he drank from, only most of them. His hunger ran deep and dark when blood touched his mouth, clawing at him to continue on. Once one was dead, could always drink another, that hunger never really went away. It was something that he could control, if he felt like it, but generally only cared when the police were getting close. At his age, he didn't need to drink often for sustenance, Jack merely enjoyed the kill.
The night was made for Jack. The shadows, the silvery light of the moon, and tonight there was a thick London fog making its way through the village. It all reminded him of his most infamous kills, but that did not bring the smirk it should have to his lips. Jack was proud to be a famous mystery, but those days, that pain and reason for the deaths, his Mary Kelly, made him want to rip apart any female he saw that wasn't Victorian level chaste.
Jack heard the footsteps, light and dexterous, jogging toward him. He wiped the blood from his chin, staining his hand instead, and sliding the knife he had used in his latest attack into its sheath hidden at his waste band. The knife was used to make the initial injuries to cover up the vampiric nature of the attack and his bite pattern. Eyes black, he waited for the jogger to stumble upon the dead body. Distract the girl so he assess if she had a compulsion amulet and attack if she didn't.