Ernest McCormack's Murder of William Hallack

On the night of September 14, 1922, someone shot and killed twenty-one-year-old service station attendant William Hallack as he was getting ready to close the Standard filling station where he worked at the corner of Jefferson and Center (i.e. Central) in Springfield. William McCormack, a twenty-two-year-old Springfield man, was quickly identified as a suspect, and he was arrested the next morning at his parents' home on East Monroe. Taken to the Greene County Jail, McCormack made a full confession later the same day.
He said he was with another young man, Harold Willey, on the afternoon of the 14th when the idea came to him to rob the filling station, because he wanted money to go to Kansas City the next day with Willey and his family. However, he said he never mentioned his plan to Willey and that he went back to the station that night alone with plans to hold it up. When he told the attendant to put up his hands, Hallack started to comply, then laughed and dropped his hands, saying "You can't fool me." McCormack panicked and shot the man with a .45 Colt pistol. He then started running without taking time to try to get any money. He raced north, threw the weapon into Jordan Creek as he crossed the trestle on Benton Avenue, and proceeded to his home on Monroe.
McCormack's account of what happened, however, conflicted with several reports from eyewitnesses. According to at least one or two of the reports, two men in a car had stopped near the filling station about the time of the holdup, the passenger got out while the driver remained in the car, and the passenger soon jumped back into the car as it took off.
A day or two after the crime, it was reported in a Springfield paper that McCormack was recently discharged from the US Navy. In fact, according to military records, McCormack was a deserter, having absconded while stationed in the state of Washington. Later it was also reported in Springfield that McCormack was on parole from a robbery charge in the state of Washington. So, it's possible that the arrest for robbery had something to do with why he was listed as a deserter in Navy records.
Investigators soon discounted the eyewitness accounts suggesting that McCormack might have had a getaway driver, because the shooter's insistence that he left the scene on foot was corroborated by other witnesses. Witty was nonetheless arrested as an accomplice to the crime after McCormack changed his story and admitted that he had discussed the idea of robbing the station with Witty ahead of time and that he obtained the pistol he used in the crime from Witty. Also, McCormack now claimed that he had discharged the gun accidentally when he killed Hallack.
Nevertheless, when his case came up in November, he pleaded guilty to first-degree murder. A Springfield reporter remarked at the time on how unusual it was for a person to plead guilty to a first-degree murder charge. Defendants often pleaded guilty to second-degree murder, especially if they had originally been charged with first degree murder, but rarely did anybody admit to first-degree murder.
At Witty's preliminary examination in December, McCormack, whom the prosecution was counting on to be its star witness, changed his story again and said he'd lied about discussing the idea of robbing the station with Witty ahead of time. He did admit that he borrowed the gun from Witty, but he said Witty did not know what he wanted it for. Considering McCormack's testimony, the state dropped its charges against Witty.
In January 1923, McCormack was sentenced to life in the state penitentiary at Jefferson City. He was paroled, however, in 1943 after serving a little over twenty years. He was discharged altogether in 1948, and he got his citizenship restored the next year.