FRANKLIN, Ind. -- A man was charged with murder Wednesday after he followed through with what he described as a suicide pact with his fiancee, police said.

Johnson County Prosecutor Brad Cooper said James Adam Betts, 24, told police differing stories, but Cooper said that Betts contended he and Christina Santana, 29, had agreed to kill themselves and had written each other a note that expressed that desire.

Betts said that he and Santana had sex in a barn on his grandfather's farm on May 6 before he, a former butcher at a Marsh grocery store, used a butcher knife to cut her neck. Betts originally told police that Santana had cut her own throat.

"Miss Santana was supposed to go first, then Mr. Betts was supposed to complete the act," said Johnson County Sheriff's Department Maj. Steve Byerly. "He told everybody -- the EMT people, fire people, detectives -- that she cut her neck."

After he made several cuts but saw that Santana wasn't dying quickly enough and that the knife wasn't "sharp enough to do the job," he tried to snap her neck by shaking her violently, Johnson County Sheriff's Detective Kirby Cochran said.

Betts told police that he held Santana for about two hours and fell asleep. When he woke up, he decided he should tell his grandfather what had happened.

Emergency medical responders took Santana to Methodist Hospital, where she died.

Betts was originally arrested on a charge of assisting suicide, but later admitted to police he had killed Santana and was charged with murder.

"He wanted to truly get what happened off his chest. That's when he admitted it was him alone, he provided the knife, but it was him alone that made the cuts and took her life," Byerly said.

The prosecutor said the murder charge is justified, whether Santana truly wanted to kill herself or not.

"If a person actually performs the act and kills another person, whether the person wants to commit suicide or not, Indiana law is clear that is defined as murder," Cooper said.

Police said the couple had apparently considered suicide after Santana lost custody of her children and Betts was despondent about his break up with another woman.