CAMDEN, N.J. — A 6-year-old boy whose throat was slashed by an intruder high on PCP-laced marijuana was killed while trying to save his sister, coming to her aid as she was being assaulted on the floor, prosecutors said Tuesday.

Thirty-one-year-old Osvaldo Rivera, who is charged in Sunday’s middle-of-the-night attack, sobbed during an appearance Tuesday in court in which bail was set at $5 million.

During an interrogation, Rivera had asked: ‘‘How bad did I hurt them?’’ assistant prosecutor Christine Shah said during the hearing.

The attack early Sunday was the second time in less than two weeks that prosecutors say a Camden resident apparently high on PCP had killed a child. On Aug. 22, a Camden woman decapitated her 2-year-old son, called 911 to admit stabbing the child, then killed herself.

Authorities said they are going to test PCP on the street to see what might be behind the outbursts of violence.

The drug can make users hallucinatory and incoherent, police said.