The man arrested a day after the murder of a Statehouse security guard was handcuffed by police just 40 minutes after the violence — but then was let go, authorities said Thursday.

Police said Derek W. Potts (search) was initially stopped because an officer thought he matched the suspect's description. They declined to say whether they searched a bag he had with him or what he told them.

Authorities said Potts did not have the shotgun used in the killing or the silver, two-door foreign car linked to the shooter. In addition, reports in the first hours of the manhunt described the gunman as having blonde hair. Potts has brown hair.

Potts, 24, is charged with first-degree murder, accused of walking into the Statehouse's main entrance Monday and shooting security guard William Wozniak (search) once in the chest, then walking away.

He was finally arrested in the case early Tuesday, 17 hours after he was first stopped outside a spaghetti restaurant. In that time, he traveled around town, visited two restaurants and changed clothes.

Springfield police were investigating whether officers followed procedure, Deputy Police Chief Jim Burton said.

Police Chief Donald Kliment said it was "unfortunate" that the officers who initially detained Potts let him go, but asked that the case be judged in its entirety.

"In the chaos that follows an event like that which occurred at the Capitol on Monday, sometimes all the relevant information is not available to officers right away," Kliment said in a statement.

Potts, a recent college dropout, is being held on $20 million bond.

Gov. Rod Blagojevich (search) and more than 300 people filled a Baptist church in Petersburg for Wozniak's funeral Thursday. Friends remembered Wozniak as a family man who loved his two teenage children and enjoyed jokes and tinkering on projects around the house.

Authorities have said they know of no motive for his shooting; the governor was not in Springfield at the time, and the Legislature was not in session.

Another guard said Thursday that Potts visited the Capitol about three hours before the shooting and wandered around the first floor for 15 minutes or so. "He looked like any other tourist," Craig Glossop said.

His mother said Potts has been institutionalized five times, and has been diagnosed with bipolar disorder, hypomania and schizophrenia.

"At times he would hear voices," she said in a letter to the Chicago Tribune. "There were times the medication worked and other times it did not."

She expressed sympathy for Wozniak's family: "We are filled with sorrow for all the suffering this horrible situation has caused for so many."

Wozniak was unarmed when he was shot and not wearing a bullet-proof vest, although a handful of vests were available. Secretary of State Jesse White, who oversees security at the Capitol, said he has never required guards to wear them.

Spokesman Randy Nehrt said Thursday that all security guards will now be outfitted with vests.

According to state records, Potts' father, William, worked for the state Department of Financial Institutions as an examiner until 2002. Authorities did not immediately comment on the father's tenure there.