(CNN) -- A man who killed himself before police could question him about the abduction of a 4-year-old Missouri girl was a convicted sex offender, a local official told CNN Thursday.
Paul Smith, 38, died from a self-inflicted gunshot wound to the head, Lincoln County, Missouri, coroner Robert Shramek said. Smith shot himself as investigators approached him late Wednesday afternoon. He died in a hospital at 10:29 p.m., Shramek said.
Smith was a convicted sex offender, according to Missouri's sex offender registry and Louisiana, Missouri, city administrator Bob Jenne.
St. Louis County Police Chief Timothy Fitch told reporters Thursday that "good old-fashioned detective work" led authorities to Smith.
"We have plenty of evidence that Paul Smith is the suspect," Fitch said in a news conference.
The girl, Alisa Maier, was found alive Tuesday night in the St. Louis suburb of Fenton, about 70 miles south of her Mississippi River hometown of Louisiana, Missouri. She was wearing different clothes than the ones she had on when she was abducted, and Fitch said they were able to trace those clothes to a particular Wal-Mart.
Store employees showed authorities transaction records from Smith's purchase of a pack of cigarettes, which in Missouri, requires the buyer to give their date of birth.
"All (investigators) had to work with was some video of this individual and his date of birth," Fitch said.
Alisa was discovered at a gas station car wash, where witnesses saw her walking away from a car with a very loud muffler, which then left the station. Fitch said Smith was familiar with that area.
The little girl's parents identified her from a photograph sent by police there, her grandfather, Roy Harrison, said Wednesday night.
"You couldn't miss the big brown eyes," Harrison told HLN's "Nancy Grace."
But the search went on for the man who abducted her, who was seen driving a dark-colored, four-door sedan with missing wheel covers and a loud muffler. A tip led police to a home in the town of Hawk Point, about 45 miles south of Louisiana, where police found a car parked outside a home that roughly matched that description, Missouri Highway Patrol Sgt. Al Nothum said.
Before police could speak to the man at the home, "He pulled out a gun and shot himself," Nothum said.
Alisa was snatched from the front yard of her home Monday evening as she played with her 6-year-old brother. Harrison said his granddaughter is "a bright young girl" who has talked "a little bit" with her parents about her abduction.
Anita McKlevis, a neighbor, told HLN's "Prime News" that the town of about 4,000 was overjoyed by the girl's safe return.
"It was like someone gave us all $1 million," McKlevis said. "Everybody is so happy for this little girl and the family. We are going to stick by the family. That's important."
McKlevis said she sent cupcakes to the family's home, "because I know she loves them."
And Harrison said the family was "ecstatic" over Alisa's safe return.
"I've told people earlier, if I could do a back flip, I would," he said. "When we get her back and get the family together, we're gonna have a barbecue and togetherness, and hugs and kisses. I couldn't be any happier."