DAVENPORT, Iowa (AP) — A former volunteer firefighter who hoped for a career in law enforcement was convicted Thursday of killing his pregnant wife, as jurors in his third trial rejected his claims that an unknown intruder shot her.

Jurors found Seth Techel, 23, guilty of first-degree murder and nonconsensual termination of a human pregnancy. He now faces a mandatory penalty of life in prison at his Sept 15 sentencing.

Prosecutors said Techel killed 23-year-old Lisa Techel on May 26, 2012, so that he could be with a co-worker with whom he had been exchanging sexual text messages for months. They said Techel shot his wife in their trailer in Agency, in rural southeast Iowa, took a shower to wash off the evidence, then made 911 calls in which he pretended to be hysterical.

Lisa Techel, a county jail employee who had hoped to become a criminal investigator, was 17 weeks pregnant with their first child. The couple had been married for seven months before the slaying divided their families, who are both well-known in the area.

Techel seemed to show no emotion at the verdict. His parents and grandfather — former Ottumwa Mayor Dale Uehling — hung their heads in the first row of the courtroom. Lisa Techel’s father, sheriff’s deputy Todd Caldwell, wiped away tears after the 12 jurors each agreed with the guilty verdicts.

“I knew that justice would prevail,” said Caldwell, who works for the Wapello County Sheriff’s Office, which helped investigate his daughter’s slaying. “It’s just a matter of how long it would take.”

Jurors at two previous trials last year had been unable to agree on a verdict, leading to mistrials. The jury this time deliberated for four hours over two days.

Caldwell said the verdict means his daughter “can rest, and we can start to heal as a family.” He said he was disappointed that Techel — whom he had recommended for a job at the county jail — didn’t display emotion.

“I want to know that it sunk in to him that he couldn’t get by with this and that the truth would come out,” Caldwell said.

Lisa Techel’s sister, Presley Caldwell, said Seth Techel had been like “a second brother,” and it was emotional to watch deputies handcuff Techel and lead him out of the courtroom.

“It just is more real when you actually see he was apprehended and he’s gone for life now,” she said. “It’s hard for me because I lost Lisa and my best friend at the same time. He’s not now. He’s a monster. But it’s hard to let all that sink in.”

The texts between Techel and Rachel McFarland, who worked together at a job training center in Ottumwa, “read like a countdown to Lisa Techel’s death,” Prosecutor Andrew Prosser had told jurors. He said the messages in which Techel suggested he was leaving his wife to be with McFarland the day before the slaying gave him the motive to kill his high school sweetheart.

Techel had told police that he was in the shower that May morning when he heard a gunshot, came out and saw his wife wounded in their bed. He is heard on the audio of 911 calls sobbing as he says, “my wife’s been shot” and requests an ambulance.

His lawyers had argued that was the emotion of a man who witnessed his wife dying. Prosecutors suggested they were fake tears.

Both sides made key strategic shifts for the third trial.

Defense lawyers had previously argued that the real killer was likely Brian Tate, a mentally ill neighbor who had feuded with Seth Techel and has since died. This time, they said Tate could have committed the crime but suggested other possibilities such as a co-worker with whom Lisa Techel had an affair. They also painted the investigation as incompetent.

Prosser and Scott Brown, prosecutors for the Iowa Attorney General’s Office, streamlined their case and spent more time preparing for jury selection this time. Both said it was their first time they’ve tried the same defendant three times, which added to their nerves before the verdict.

“That took what would otherwise be an emotional situation and just compounded it, because it’s been going on for so long,” Prosser said. “I’m thrilled … that we finally got to a conclusion.”

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