Two mounted Indiana police officers
Mounted police officers watch an entrance. An Indiana man walked into a police station in Danville and recently confessed to killing his girlfriend almost five years ago. KAREN BLEIER/AFP/Getty Images

More than four years after the shooting death of his girlfriend, an Indiana man walked into a police station Sunday and allegedly confessed to killing her.

The Danville Police Department said in a statement Monday that Connor Warren Scott, 24, admitted to killing Kaylyn Whitaker, 20, at his home in Clark County, Illinois, on Halloween in 2014. Investigators had originally ruled Whitaker's death a suicide but 10 months later it was ruled a homicide.

Scott, who was charged with first-degree murder, is reportedly being held on $1 million bond at Clark County Jail.

Police say Scott had been living in Danville for about six months after moving there from Noblesville, Indiana.

While many suspected Scott's involvement in the murder, no charges were filed, which angered and confused Whitaker's friends and family.

Whitaker’s parents told MyWashbashValley.com that they were shocked when they learned from Illinois State Police at 5:00 a.m. on Monday that Scott had turned himself in.

"Then I'm at work and she calls and says he confessed on his own and I'm thinking I wouldn't have guessed that one," Dave Whitaker, Kaylyn Whitaker's father, said. "I wouldn't have guessed. I really thought he thought he was going to get away with this."

Illinois Appellate Prosecutor Ed Parkinson, who is in charge of the case, considered it a homicide from the very beginning.

"It is my opinion that Kaylyn could not have shot herself in the location where the bullet entered her skull," Parkinson stated in a written review. "The amended finding as a cause of death as a homicide best fits the situation in this case."

It is not clear as to why Scott confessed. Details about the contents of the confession have not been released to the press.

WTHR, an NBC affiliate in Indianapolis, reported on Monday that Danville police had confiscated firearms registered to Scott on Feb. 6 after his current girlfriend reported he was suicidal.

The firearms taken from Scott were done so under the "Red Flag Law," gun control legislation which allows police to take firearms from those they deem mentally unstable or dangerous.