As charges were filed Friday against a St. Paul man who allegedly beheaded a pet dog, police said they'd uncovered a gruesome new twist in the case.

A search of the man's home turned up a video clip showing the dog's decapitation by chain saw. The dog was already dead when its head was severed, officials said.

The footage was found on a cell phone belonging to Anthony Albert Gomez, 24, who was charged Friday with killing a companion animal and cruelty to a companion animal, both committed with the intent to threaten, intimidate or terrorize another person. Police would not release the video.

The dog, a 4-year-old Australian shepherd mix named Chevy, belonged to 17-year-old Crystal Brown. Her family said Crystal had spurned Gomez's advances, so they believe he killed the dog and delivered its head out of spite.

When talking to police, Gomez claimed that Crystal witnessed the pet's beheading. But police and Ramsey County Attorney Susan Gaertner said there is no reason to believe Crystal was present.

Hearing that Gomez claimed she was involved sent Crystal into a fit of depression, said her grandmother, Shirley Brown. Crystal vehemently denies being present and wants to take a lie detector test to prove it, her grandmother said.

"He's dragging her down to get revenge. He was mad because she has a new boyfriend. Crystal is just severely depressed. She's on the edge ... and I don't know what will happen," Shirley Brown said.

Publicity about the case has generated interest from around the world. Crystal has received letters of condolence, pictures of pets, dog toys and treats, gift cards and checks, from as far away as Australia.

Crystal has a new puppy now, another Australian shepherd that she's named Diesel.

Gaertner and Humane Society state coordinator Jill Fritz said the case is like nothing else they've encountered.

"You keep thinking, 'Well, I've seen it all.' And you keep getting disappointed. I guess if you're sick enough to [behead an animal] in the first place, it's not that big a stretch to ... video record it. But I'm shocked, and that takes a lot," Fritz said.

"It's really appalling. It's hard to imagine what would possess a person to do something like this," Gaertner said.

Gomez is being held in the county jail in lieu of $20,000 bail. The felony charges that Gomez faces each carry a maximum sentence of four years in prison.

St. Paul Police Sgt. Jim Gray said police have interviewed a second suspect who has denied involvement in the case and has not been arrested. But the investigation is continuing, he said.

Crystal's family said the dog had been her friend and comfort as she struggled to overcome mental illness problems and a life that has included abandonment by her father and drug abuse.

The dog disappeared Feb. 7; three weeks later, a package arrived at her grandmother's home addressed to Crystal. Inside was Valentine's candy and the dog's head inside a garbage bag.

During a search of Gomez's home police found evidence of blood splatter in the basement and the cell phone with the video clips of the beheading in his bedroom, Gray said.

The video clips do not show the face of anyone who was present when the beheading occurred, he said. The dog was dead before the beheading, but police have yet to determine how it died, Gray said.