Just hours after the verdict was read in the biggest case of his career, veteran Assistant State Attorney Jeff Ashton announced he will retire at the end of the week.

Ashton’s last day at the Orange-Osceola State Attorney’s Office, where he has worked for 30 years, will be Friday, a spokeswoman for State Attorney Lawson Lamar said this afternoon.

“It’s a personal matter,” said Danielle Tavernier. “He and Mr. Lamar have spoken about this and it comes as no surprise to him [Lamar].”

It’s unclear what Ashton plans to do in his retirement or if he will be seeking another job. He was one of three assistant state attorneys assigned to the Casey Anthony first-degree murder trial.

Tavernier said the decision to retire was Ashton’s alone.

“He has been with this office for 30 years and there is no question about his dedication,” she said.

Ashton was one of the first prosecutors in the nation to use DNA evidence in court in the 1990s. And he was the first prosecutor in the nation to argue the air sample science he presented in the Casey Anthony trial.

Since the start of this case, Ashton served as the emotional, bombastic counter to prosecutor Linda Drane Burdick’s sedate and measured approach on the prosecution team.

As his courtroom performance showed, Ashton has a deep understanding of the science used to support the state’s case, especially the decomposition odor and chloroform findings from Casey Anthony’s car trunk.

He also managed to break up certain defense testimony and questioning with his many objections. But his real strength showed when he cross-examined defense expert witnesses.

Ashton, for example, made forensic pathologist Dr. Werner Spitz look somewhat out of touch and unfamiliar with the case. And he cast serious doubt on Spitz’s findings that Caylee’s remains were positioned and duct tape placed on them after decomposition. He reiterated in his closing that Spitz’s claims were “incredible” and lacking believability.

Ashton, 53, was known to bicker in court with the defense, which prompted Chief Judge Belvin Perry to admonish both parties during hearings.

In the last death penalty case he tried — several weeks before the Casey Anthony trial started — Ashton so thoroughly frightened the defendant that the man changed his plea to guilty before jurors got to weigh in with a verdict. Ashton agreed to a life sentence in that case.

Ashton graduated from the University of Florida‘s law school in 1980. He was hired by the Orange-Osceola State Attorney’s Office in January 1981 replacing Bill Vose, who is now the Chief Assistant State Attorney.

Ashton has handled other high profile murder cases, including the prosecution of John Huggins, the man convicted strangling Carla Larson, a construction engineer working at Walt Disney World in June 1997.