Chilling new details released in case of mom, son charged in murder of girlfriend

CALIFORNIA, Pa. (WPVI) -- There are new chilling details in the case of a mother and her teenage son charged in the fatal stabbing of his girlfriend, a college freshman, outside of Pittsburgh.

Authorities are releasing new evidence, including a surveillance image showing Royce and Rachel Moser allegedly after the killing. They say Royce can allegedly be seen wearing blue latex gloves.

Other images appear to show blood in the trunk of the victim's SUV and discarded knives.

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Prosecutors allege Royce lured Karoline Heintz to his home two weeks ago and stabbed her twice in her vehicle. He allegedly told investigators he got angry and had a 'demon take over' him.

Her body was later found inside her Jeep parked just blocks from PennWest California University on August 20.

According to a police affidavit, the son allegedly told police his mom helped clean the car, wash his clothes and put the knives into a garbage bag.

Prosecutors also say the son made a series of online searches: "what removes fingerprints from objects" and "can an 18-year-old get the death penalty?"

Moser, 18, is charged with criminal homicide, and his mother is charged with hindering apprehension, tampering with evidence, abuse of a corpse and obstruction.

During a hearing this week, a judge upheld all charges against Royce Moser and added a new charge for Rachel Moser: criminal use of a communication device, WTAE reported.

ABC News contributed to this report.