"It's the worst set of circumstances, the worst set of facts, that I've ever tried," said Lucien Sammons, Jr., the Doddridge Cunty prosecutor. "It was just a terrible case."

David Keigley showed no emotion as the verdict came in: guilty of first-degree murder and guilty of death of a child by a parent.

He had pleaded guilty earlier to incest and sexual abuse by a parent.

After more than three hours of deliberations, the jury did not recommend "mercy" for Keigley, which would have made him eligible for parole after 15 years for the murder charge.

Keigley's sentencing is set for Dec. 20.

The four-day trial ended a more than 15-month search for Mariah Keigley's killer. The prosecution called witness after witness to prove David Keigley smothered his daughter with a garbage bag to cover up her pregnancy.

The key evidence was a taped confession from Keigley two days after the crime.

"Otherwise, it would have been a circumstantial case and it would've been more difficult," Sammons said.

Jurors didn't buy Keigley's defense that his live-in girlfriend, Amber Starr, killed Mariah out of jealousy.

But prosecutors do allege she helped her boyfriend cover it up.

"I argued that the whole thing with his testimony was a smokescreen," Sammons said.

Instead, Sammons argued Keigley fought to maintain control of a daughter who was 7 months pregnant -- and about to leave on a summer vacation with her aunt.

Keigley asked Mariah to stay one last night before she left. He told her aunt -- his sister -- to pick her up "tomorrow."

"For Mariah," Sammons said, "tomorrow never came."