Story highlights Donald James Smith, 56, faces charges

Smith had promised to buy the girl's family clothes and hamburgers, a sheriff's official says

Cherish Lilly Perrywinkle's mother reported Friday night that she was missing from a Walmart

"We are very confident" Smith took her from the store, a police spokesman says

The body of an 8-year-old girl who was abducted Friday night from a Walmart in Jacksonville, Florida, was discovered Saturday morning, police said.

"This is a transition from an abduction investigation to a murder investigation," Jacksonville Sheriff's Office spokesman Shannon Hartley told reporters. "Obviously, we have the unfortunate answer that we didn't want to have."

Donald James Smith, 56, faces kidnapping and murder charges. He was listed as being held without bond Saturday night.

Smith is a registered sex offender who was released from custody on May 31, according to Michael Williams, director of the sheriff's investigations department. Authorities from the sheriff's office had just made contact with him to verify his address on Friday morning, Williams said.

Later that same day, a woman called police to report that her daughter was missing from the Walmart.

Authorities initially called on the public to help find Cherish Lilly Perrywinkle, who had been wearing an orange sundress, purple flip-flops and a pink ribbon when she went missing.

Suspect Donald James Smith has "a very extensive criminal history" that includes a kidnapping conviction.

After the investigation revealed that the girl had been abducted, an Amber Alert was activated, Hartley said. He identified Smith, "a man with a very extensive criminal history" that included a kidnapping conviction, as a suspect.

Williams said the girl's mother first met Smith on Friday night at a local Dollar General store, where he offered to take the family to Walmart to buy them some clothes.

"After being inside the store for a couple hours, the man then offered to buy some hamburgers," Williams told reporters. "As he walked to the front of the store, he took our 8-year-old victim with him. They walked to the front of the Walmart toward the McDonald's. They did not stop at the McDonald's. They walked outside, got in his van and left the location."

On Saturday morning, police stopped Smith, 56, as he drove a white van southbound on I-95 in Jacksonville and detained him without incident, Hartley said.

"Obviously, having Mr. Smith in custody is a huge break for us," he said as the search for the girl was continuing. "We are very confident that he was the one that took her from the Walmart."

Soon after, Hartley said in a subsequent news conference, police followed a lead that took them four miles from the Walmart to a church, near which the child's body was discovered.

According to records from the Duval County Clerk of Courts, Smith's most recent convictions occurred last year on charges from 2009 for unlawful impersonation of a public employee and aggravated child abuse by willful torture, for which he was sentenced to a year in county jail.

"The first thing I would tell you is, as a parent, hug your children closely right now and know where they're at," Hartley said. "Just pay attention to them, keep them close."