Neighbors are shaking their heads in shock after a 71-year-old man was beaten and stabbed to death in his home, and his teen granddaughter and three friends were charged with the homicide.

“Over money, your own family, it’s just a disgrace,” neighbor Ronald Briggs told WNEP-TV in wake of arrests in the brutal beating and stabbing death of Joseph Monka in Edwardsville, Luzerne County.

The motive?

Police tell WNEP that Monka’s granddaughter, Gabriella Elizabeth Long, 17; her boyfriend Christopher Brian Cortez, 19; Mercedes Lin Hall, 16, and a fourth suspect all conspired to stab Long’s grandfather inside his home, then made off with $30,000 in cash from his basement safe and stole his car.

The three teens were arrested early Thursday at a hotel near Wilkes-Barre. The fourth suspect, Devin Malik Cunningham, 20, of Wilkes-Barre, remained on the loose at last report.

All four face charges of criminal homicide, conspiracy to commit murder, theft, conspiracy to commit theft, unauthorized use of a vehicle and tampering with evidence.

Monka's body was not found until Wednesday -- two days after the killing and only when other family members began to look for him, WNEP reports.

Monka’s bloody body was discovered underneath a large dresser on the second floor, the Citizens Voice writes in a detailed account.

The 71-year-old grandfather had been beaten with a golf club and stabbed in the neck until dead, police say.

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A neighborhood is in shock after a teenager and her friends are charged with murder. The victim is the girl's own grandfather.

https://t.co/yNdq2gs6CC — WNEP (@WNEP) April 18, 2019

The chilling facts of the case do not make it any easier to understand.

As Briggs added to WNEP: “This is a quiet area. Everyone around this area knows each other.”

Not too well, apparently.