Ridulph was 7 years old when she was murdered. Her body was found five months after she disappeared from her Sycamore home.
The girl's body was exhumed Wednesday after officials consulted her family.
"Although the events are 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," Charles Ridulph, victim's brother, said.
A team of 20 forensics experts are now examining Ridulph's remains. They hope more than half a century of scientific advances -- including DNA -- will yield clues and pinpoint a cause of death in the 53-year-old murder case. Ridulph's death was listed as "foul play" in 1958 after her remains were found.
"We want to bring the best minds available to us to have them conduct a thorough examination of her remains to see if that gives us any new information," DeKalb County State's Attorney Clay Campbell said.
In 2008, authorities began to reexamine the case. Earlier this month, former Sycamore resident Jack McCullough, 71, was arrested and charged with Ridulph's kidnapping and murder. McCullough now lives in Washington State. He was extradited to Illinois on Wednesday and is expected to be arraigned in DeKalb County as early as Thursday morning. He is being held on $3 million bond.
"We are carefully reviewing every single statement Mr. McCullough has made from 1957 until today," Campbell said. McCullough used to go by the name of John Tessier. He says he has an alibi for the day Ridulph disappeared -- a military medical examination in Chicago.
"Jack McCullough is my father. I love him. I believe in him. And I know he didn't do this," Janie O'Conner, suspect's stepdaughter, said.
Authorities recently recovered an unused train ticket from Rockford to Chicago on the day Ridulph disappeared. McCullough's high school sweetheart said that ticket was tucked behind a photograph and inside a picture frame given to her by McCullough.
"It was just astonishing that somebody would keep that for as long as they have," Brion Hanley, Illinois State Police, said.
"We've been fairly astonished at the, not only at the leads that we've gotten, but the recollection of some of the local residents, and they've been absolutely critical in assisting us in this case," Campbell said.
Anyone with information is asked to call a tip line at 1-800-843-5763.