A Seattle man identified as an ex-cop was arrested for killing a seven-year-old Chicago-area girl 54 years ago.

The former cop was in Illinois on Wednesday as the remains of seven-year-old Maria Ridulph, who was murdered five decades ago, were unearthed by the investigators.

The former cop, Jack McCullough, 71, has been charged for allegedly killing Maria Ridulph, whose remains were found in 1958, about 100 miles from where she went missing, the Daily Beast reported.

Back in 1957, Maria was kidnapped from near her house in Illinois, where she was playing with her friend Cathy Sigman. Maria's playmate, Cathy recalled that a man calling himself Johnny came and asked Maria if she wanted a piggy-back ride. Cathy went inside to get her mittens but when she returned both Ridulph and the man were missing.

When Ridulph was seven-year-old, McCullough was a teenager known as John Tessier.

McCullough went on to join the military, where he changed his name to Jack McCullough from John Tessier.

McCullough at the time had an alibi who said that he was on a train from Rockford to Chicago after undergoing examinations for determining his eligibility for military service.

Investigators have also called McCullough's ex-girlfriend for questioning. She told authorities that she had seen the train ticket that had not been used, Reuters reported quoting court papers.

Investigators then tracked down Maria's playmate, Cathy who was playing with Maria when she disappeared and identified McCullough's photo out of a montage.

McCullough was arrested on June 29, in Seattle and was charged in a Washington state court on charges of being a fugitive.

On July 1, prosecutors in DeKalb County, Illinois charged him with the murder of Maria Ridulph. On Wednesday he was removed from King County Jail Court and returned to Illinois.