ONE PHOTO SHOWED a blonde woman with a red ball in her mouth attached to a leather strap that wrapped around her head, her head tilted toward the camera.

The other was a close-up of a slain blonde woman, slightly decomposed and covered in dirt and debris, with a similar red ball in her mouth and a similar leather strap wrapped around her head. She had been stabbed to death.

The first photo was of Canadian porn model Natel King.

So was the second.

The similarities are more than a coincidence, authorities say.

Montgomery County District Attorney Bruce L. Castor, Jr. believes Anthony Frederick – the photographer who took the first picture – murdered King during a bondage shoot that went awry, then dumped her body down an embankment in Whitemarsh Township. A woman spotted her body on March 23 and called authorities.

Yesterday, the crime-scene photo was just one of dozens of gruesome images Castor introduced as evidence at a two-hour preliminary hearing for Frederick, 46, and his assistant, Jennifer Mitkus, 29.

Castor also revealed that DNA tests show that King’s blood was found on a plastic bucket and on a receipt in the basement of the Conshohocken studio Frederick used. Castor is still awaiting final results from blood samples taken from Frederick’s car and other spots in the studio. Sperm found on King was too degraded to be of any use, he said.

After the hearing, District Justice Deborah Lukens held Frederick for trial on first- and third-degree murder charges, abuse of a corpse and possessing an instrument of crime. She held Mitkus for trial on charges of lying to authorities and of hindering apprehension.

But Castor said more serious criminal charges may be coming for Mitkus, who told authorities King had left the Conshohocken studio after they finished filming the bondage video on Feb. 29 to go to a nearby pub.

“Clearly we believe that Jennifer Mitkus lied about her [King] leaving there alive, so the likelihood is either she participated in the murder, which we’re investigating, or knew about it after the fact and assisted in the disposal of the body. Otherwise, there’s no reason to lie,” he said.

“That’s the thing that has me puzzled…, ” he said. “There’s no reason to lie about that unless she has other knowledge that’s incriminating, and I’ve got to find out what that is.”

Defense attorneys for both defendants insisted their clients are innocent and pointed out that they both had given voluntary statements to police.

“The fact that there is some connection between the victim and my client, that was certainly proven beyond any doubt because my client admitted that,” said Daniel-Paul Alva, one of Frederick’s defense attorneys. “He led police to all the physical evidence and said, ‘Here. Indeed. I do take photographs like this. She voluntarily submitted to these photographs. She got paid for these photographs. After she was paid, she left the studio and I never saw her again. I’m sorry she’s dead.’ There is no evidence here whatsoever.”

Frederick told police he had done two photo shoots with King on the morning of Feb. 29 at the Hampton Inn in Oaks, Montgomery County. They left there, met up with Mitkus at the Perkiomen Hotel, then went to the studio in Conshohocken. Frederick provided memory cards from his digital camera for the shoot at the Oaks. One of the pictures from the cards shows King, who called herself the “Sexy Canadian,” with the red ball in her mouth. Frederick said he had erased all the images from the Conshohocken shoot.

Carolyn Carluccio, one of Mitkus’ defense attorneys, said she was not sure what her client supposedly had lied about. She did convince the judge to lower Mitkus’ bail from $100,000 cash to 10 percent of that, provided she has a verifiable address at the time of release. Mitkus had no permanent address when she was arrested.

Police found King’s 1992 red Saturn coupe in front of the Conshohocken studio on March 5, which is why Castor believes Frederick and Mitkus gave statements to cops.

“The car is still there,” he said. “They have to cooperate a little bit. They have to do the minimum they can, to keep the police at bay.”