TRENTON, N.J. >> A man high on PCP-laced marijuana stabbed two neighborhood children in their home while they slept, killing a 6-year-old boy and critically wounding his 12-year-old sister, authorities said.

Osvaldo Rivera was found hiding between a mattress and a bedroom wall Sunday afternoon inside a Camden apartment and was charged Monday with murder and attempted murder, said Jason Laughlin, a spokesman for the Camden County prosecutor’s office.

The attack was the second recent one in Camden, an impoverished city across the river from Philadelphia, involving a child and a suspect said to be high on PCP and marijuana.

Rivera, 31, was being held in jail awaiting arraignment, which Laughlin said will likely be held Tuesday. Laughlin didn’t know if Rivera had an attorney.

Police found blood-stained sneakers inside the apartment where Rivera was arrested that matched bloody footprints in the home where Dominick Andujor was stabbed to death, Laughlin said. The boy’s 12-year-old sister had her throat slit while she slept in another room. She remained hospitalized Monday at Cooper University Hospital in Camden. The hospital, though, has declined to discuss her condition, citing privacy reasons.

While being questioned by investigators, Rivera said he had smoked a combination of marijuana and the hallucinogenic drug PCP before the attack, Laughlin said.