PAINESVILLE -- A Lake County jury has found Kevin Knoefel, 43, of Willoughby Hills guilty of conspiracy in the murder of his wife.

Prosecutors say he used his sexual relationship with his foster daughter, then 17, to conspire to kill his wife.

Jurors deliberated three hours Tuesday and about six hours Wednesday before reaching a verdict.

A jury of seven men and five women found Knoefel guilty of murder conspiracy and complicity in the fatal stabbing of his 41-year-old wife Lisa. He was also convicted for six counts of sexual battery for preying on Sabrina Zunich, now 19. Zunich faces murder charges for allegedly stabbing Knoefel to death in November 2012.

"This man did not get away with this crime. It was a very difficult case for the state in terms of if the jury would believe Sabrina Zunich, and we're just very gratified they saw their way through some of the arguments that were made about her mental illness," said Lake County Assistant Prosecutor Karen Kowall.

Zunich testified that she was in love with Kevin Knoefel, and the two of them planned the slaying so they could be together.

Zunich testified Knoefel told her Lisa was "worth more dead than alive," and helped plan the details down to the knife that was used in the act.

Zunich was arrested immediately after the incident. That's when she started to work with prosecutors, telling them her version of the crime.

"[We] didn't expect to believe her," said Kowall, "As we listened to the story unfold, it made complete sense to us. And filled in some gaps."

Kowall says the evidence also added up: he had collected a life insurance policy worth almost $800,000 soon after her death.

"It was astounding at the speed that he did that and the speed that he spent it," she said. "[Zunich] had been manipulated by this man…manipulated to commit these crimes."

Kevin Knoefel's attorney said that the now-19-year-old Zunich is mentally ill and acted alone.

"I think Sabrina Zunich murdered Lisa Knoefel," said Michael Connick, who represented Knoefel.

As to Knoefel's role: "Nothing. He had no role," said Connick. He says there will be an appeal.

A friend of Lisa's told reporters while leaving the courtroom, "[Kevin Knoefel] did a heinous act, and took advantage of people. So now Lisa can rest."

Knoefel faces a maximum sentence of life in prison without parole. No sentencing date was set.