LA CROSSE, Wis. -- The prosecution grilled a West Salem man accused of killing his parents for money about why he lied to investigators.

Eric Koula is on trial for the shooting deaths of his parents Dennis and Merna Koula in their Barre Mills home in May 2010.

Koula has admitted lying to investigators about some of his actions surrounding the deaths of his parents.

Through Tuesday’s questioning, the prosecution tried to convince the jury the reason Koula misled police was to cover up his own tracks.

The jury could hear Koula sobbing during a recording of his conversation with a 911 operator on May 24, 2010. It was the day Koula said he found his parents’ bodies.

But the prosecution said it was all a show, just like the time he pretended to be upset about the note reading "fixed u" he admits planting in his own mailbox shortly after the murders.

"You pretended to be crying?" asked prosecutor Gary Freyberg
"I was upset, yes," said Koula.
"You pretended to be crying, right?" asked Freyberg.
"I was thinking about my son," said Koula.

Koula said he planted the note because he was worried the police were starting to focus on his teenage son.

But that's not why the prosecution is arguing he did it.

"That note was designed to send the police off chasing somebody who didn't exist, right?" said Freyberg.
"That's what it did, yes," said Koula.
"You knew you were planting false evidence, didn't you?" asked Freyberg.
"Yes," said Koula.
"You knew you were planting false evidence with the intent to mislead the people who were working to find the person who murdered your parents?" asked Freyberg.
"That's what it did, yes," said Koula.

The prosecution also argued Koula didn't come clean about planting the note until police said they knew he was lying -- just like the $50,000 check he'd signed in his father's name, dated the day of the murders and deposited the day after.

"Basically what you want to do here in your testimony is to convince the jury that you're just a liar, but not a murder. Is that right?" asked Freyberg.
"I lied about the check. I lied about the note. I did not kill my parents," said Koula.
"But there's one more big lie out there, isn't there?" asked Freyberg.
"Meaning what?" asked Koula.
"That you killed your parents," said Freyberg.
"No, I did not kill my parents," said Koula.
"Can you come clean on that?" asked Freyberg.
"I did not kill them," said Koula.

The defense argued it wasn't Koula who killed his parents, but a professional killer. They called expert witness William Tobin to the stand Tuesday afternoon to testify to that theory. Tobin said there are a three reasons these murders were consistent with a professional hit.

"The three primary bases are the choice of firearm caliber -- and that would be 0.22 caliber, for several reasons-- the fact that there were no cartridge cases recovered, as I was told or advised, and the placement of the wounds on the victims are consistent with professional hits," said Tobin.

The prosecution also argued Koula was capable of accurately handling a weapon. Koula testified to using a 0.22 caliber rifle to shoot small animals from distances of about 20 feet.