By Kelly Werthmann

GREELEY, Colo. (CBS4)– The case of a man charged in a near four-decades-old murder mystery is now in the hands of a jury. Steve Pankey is accused of kidnapping and killing 12-year-old Jonelle Matthews in Greeley in 1984.

(credit: CBS)

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Jurors in Weld County were given the case around noon Tuesday following weeks of long and often emotional testimony from dozens of witnesses. Even though there is no DNA evidence linking Pankey to the crime, prosecutors are confident he is responsible for Jonelle’s disappearance and death. Yet during closing arguments, the defense reminded the jury again that just because Pankey was obsessed with the Jonelle Matthews case, it doesn’t mean he’s a killer.

“Steve Pankey is a jerk,” said defense attorney Anthony Viorst, “…a jerk is not the same as a murderer.”

In their closing argument, prosecutors said jurors should look at the case using common sense. From Pankey’s strange behavior around the time Jonelle disappeared to his knowledge of evidence never made public. They also pointed to how Pankey inserted himself into the investigation over more than 30 years, like numerous letters he sent to the Weld County DA’s office.

“This narcissist,” Assistant DA Robert Miller said pointing at Pankey, “is saying the state will not be able to solve Jonelle Matthews’ disappearance without his help, without his cooperation… writing letters asking for immunity… Why do you need an alibi if you didn’t do anything?”

Yet Viorst asked the 12-person jury to look at the case through Pankey’s eyes.

Jonelle Matthews (credit: CBS)

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“Mr. Pankey, as we’ve heard, lives in a world of conspiracy, paranoia and self-esteem issues,” he said.

Pankey chose to take the stand in his murder trial and admitted he is a liar, a self-proclaimed “master manipulator.” He also testified he did not kidnap and kill a 12-year-old girl he’d never met.

“If you believe he lied when he said that, then you have the right to render a guilty verdict in this matter,” Viorst told the jury. “If you are convinced without a reasonable doubt that he lied to you.”

District Attorney Michael Rourke said it’s Pankey’s lies – over the decades and in the courtroom – that only add to the proof that he is guilty.

“The evidence in this case has proven beyond a reasonable doubt… that Jonelle Matthews was kidnapped, Jonelle Matthews was murdered, and the master manipulator did it,” he said, pointing directly at Steve Pankey.

(credit: CBS)

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It’s not known how long it will take the jury to deliberate. When a verdict is in, CBS4 will stream the decision live on CBSN Denver.

Kelly Werthmann