Lititz, Pa- They were two home-schooled Christian teens desperate to keep secret a steamy love affair that included swapping nude photos of each other over the computer.

Kara Beth Borden, 14, and her illicit 18-year-old lover, David Ludwig, were so desperate, cops say, that Ludwig killed Borden’s parents after they objected to her increasingly serious relationship with him.

Before the grisly slayings, Borden stubbornly ignored warnings from a close pal that her beau could go to jail for statutory rape if anyone found out.

“You don’t know how much we feel about each other and how much we want to be with each other,” Borden told friend Kayla Jeffries, 17, on Sept. 22.

The young couple’s relationship burst into the headlines Sunday, when Ludwig fatally shot Michael and Cathryn Lee Borden at home in Lititz, Pa., cops charge.

Then Ludwig took the girl on a 600-mile odyssey that ended Monday when he crashed his parents’ car into a tree near Indianapolis after a 95 mph police chase.

Ludwig waived extradition yesterday and was flown back to Pennsylvania, where he was arraigned on charges of murder, kidnapping and reckless endangerment.

Borden was reunited with family members in Lititz, an Amish-country town 60 miles west of Philadelphia. Warwick Township Police Chief Richard Garipoli said she was “devastated” by her parents’ murder.

Garipoli added that Kara will be considered a victim rather than a willing participant in her parents’ murders “until I hear otherwise.”

Ludwig and Borden began dating in May after meeting at an event sponsored by a home-schooling group.

Borden’s 13-year-old sister, Katelyn, said they saw each other three or four times a week – at church, at the home-schooling group and at the family’s home, a police affidavit said.

Ludwig’s close friend, Samuel Lohr, 19, said in the affidavit that the pair were having “a secret, intimate relationship of a sexual nature.”

“They exchanged inappropriate images of one another via the electronic media – computers and cellphones,” Lohr told police.

Borden’s parents opposed the relationship because Ludwig was too old for their daughter. So the couple tried to conceal the affair.

When Borden would see Ludwig, she apparently told her parents she was with Jeffries, because in a Sept. 22 online posting, the friend told Borden, “I won’t be your escape anymore.”

Jeffries made the angry comment in a conversation on Kara’s Web site on xanga.com, a site popular with teens.

“You’re 14, he’s 18!!!!!!!!!!!!!!!!” Jeffries wrote.

Borden then objects that Jeffries, who is 17, was dating a 21-year-old man.

“Huuuuuuuuuuge difference!” Jeffries replies. “It’s not illegal!”