Police in Richland Hills, Texas say Brent Troy Bartel, 39, admitted to carving a pentagram in his 6-year-old son's back because the 12th day of the 12th month of 2012 was a "holy day."

In audio recorded just after midnight on Wednesday morning, Bartel allegedly told a 911 operator about the crime.

"I shed some innocent blood," the man says.

"What do you mean, sir?" the 911 operator asks.

"I inscribed a pentagram on my son," the man explains.

"Why did you do that?" the operator presses.

"Because it's a holy day," the caller replies before hanging up.

Officers dispatched to Bartel's home discovered the 6-year-old boy shivering without a shirt.

"There was a large pentagram carved into his back which covered the majority of his back," a news release from Richland Hills police Sgt. Nathan Stringer said. "The child was found cold and shivering in the cold so officers wrapped him in a jacket."

Investigators later confiscated a box cutter, which they suspected was used to carve the religious symbol.

Bartel was charged aggravated assault with a deadly weapon and remains in custody in the Quad-Cities Jail in North Richland Hills in lieu of $500,00 bond. The child was reportedly stable after being taken to Cooks Children's Hospital.

Listen to this audio from Fox 4, broadcast Dec. 12, 2012.

[Photo: Richland Hills Police Dept.]