(CNN) -- Investigators Wednesday exhumed the body of a 7-year-old Illinois girl slain more than five decades ago in hopes that modern science will bolster the case against the man now accused of killing her.
The remains of Maria Ridulph, dead since 1957, were exhumed for tests as the 71-year-old suspect in her killing was headed back to Illinois from Seattle, DeKalb County State's Attorney Clay Campbell told reporters.
"Suffice to say science has advanced greatly, thankfully, since that time and we're hoping that advancement in science can assist us in our investigation of this case," Campbell said.
Ridulph disappeared while playing with a friend near her home in Sycamore, Illinois, about 60 miles west of Chicago. Her body was found five months later and 120 miles away.
Jack Daniel McCullough, the man now facing murder charges in her death, was an early suspect in the disappearance but had an alibi: He told police that he was at a military recruiting station in Rockford, Illinois, about 20 miles away, the evening Ridulph was reported missing.
McCullough told investigators he had been given a train ticket from Rockford to Chicago by the military, then returned home and went on a date with his girlfriend. But when police interviewed the woman again in 2010 and asked if she had any photos of McCullough, she discovered an unused train ticket from Rockford to Chicago that she said he had given her on the date of the crime.
The discovery led to McCullough's arrest in Seattle in early July. Campbell said Wednesday that McCullough was en route to Illinois from Washington state to face murder charges in Ridulph's death.
Maria's brother, Charles Ridulph, appeared at a news conference with Campbell and said the family had agreed to the exhumation.
"Although the events were very difficult and very unsettling, we understand the necessity for these things, and we are in complete agreement and thankful for the way this case is being handled," he said.