The case of ‘Adam’ immediately came to mind:

‘unidentified male child whose torso was discovered in the River Thames in London, United Kingdom, on 21 September 2001.

Dubbed "Adam" by police officers, the unidentified remains belonged to a black male, around four to eight years old, who had been wearing orange girls' shorts.

The post-mortem showed that Adam had been poisoned, his throat had been slit to drain the blood from his body, and his head and limbs had been expertly removed.

Investigators believe the child was likely from southwestern Nigeria, and that several days before his murder, he was trafficked to the United Kingdom for a muti ritual sacrifice.

To date, nobody has been charged with Adam's murder, and his true identity remains unknown.’