CAMDEN - Police are trying to determine if a contaminated batch of PCP is going around Camden after a child was decapitated and two other children's throats were slashed by people believed to be using the illegal drug.

They've begun analyzing batches of PCP for something that would cause such violent behavior.

A 6-year-old boy was killed Sunday trying to save his 12-year-old sister when they were assaulted in their home. Police say both were asleep when someone cut his throat then attacked his sister.

Police say the man charged, Oswaldo Rivera, admitted he smoked PCP in the hours before the attack. The 31-year-old is charged with murder and attempted murder, but more charges are likely.

Also preliminary tests on a woman who decapitated her child then killed herself showed she had PCP in her system.

Police: Arrest made in stabbing attack on sleeping kids Boy, 6, stabbed to death in NJ home; sister hurt Camden mom who decapitated son recently passed drug test Camden mom called 911 before decapitating toddler, killing self

AP wire services contributed to this report.