LA CROSSE, Wis. -- Testimony is over in the trial of a West Salem man accused of shooting and killing his parents over money.

Eric Koula is accused of killing his parents Dennis and Merna Koula in their Barre Mills home back in May 2010.

The defense is trying to prove a professional killer is responsible for the murders.

On Friday, the prosecution called an FBI expert specializing in violent crimes to the stand.

He's been analyzing crime scenes for 15 years and said in his experience, crimes with similar evidence have never been the work of a hit man.

"Have any of those that I've described that you worked, .22 caliber gun, shot to the head and no shell casings at the scene, were any of those professional killings?" asked the prosecution.

"No they were not," replied FBI witness Robert Morton

The defense and prosecution will make their closing arguments on Monday.

The jury will then go into deliberations.

The jury already gave up three weeks of their time for this trial, but their biggest challenge is still ahead of them.

Next week they will begin the process of deciding whether Koula is guilty of killing his parents.

Once they start deliberating, there's no time limit for when they will make a decision.

Now that testimony is over and Koula's fate will soon rest in the hands of 12 citizens, the jury.

"Ultimately the jury is going to have to decide whether or not the evidence that suggests Mr. Koula might have done it is enough to convince them beyond a reasonable doubt that he did do it," said Jim Kroner, an attorney with Moen, Ehrsam and Kroner.

Both sides of the case have done their best to convince the jury of Koula's role in the killings.

"The primary strategy in the defense as best I can tell is to point out the evidence that the state doesn't have," said Kroner. "The prosecution has a very strong circumstantial case based on the opportunity and motive that the person they're accusing, Mr. Koula, committed the murders."

Once the jury starts deliberations, sequestered, meaning they will essentially be kept away from the rest of the world.

"You would not be allowed outside communication so except in the company of the sheriff's deputy," said Judge Scott Horne with the La Crosse County Circuit Court.

It's a job and sacrifice that no one is taking lightly.

"They don't seem to be getting bored or falling asleep as sometimes can happen. It looks to me like they are taking their job very seriously and we can anticipate that they're going to do a great job," said Kroner.

"We are deeply appreciative and I keep saying this but I mean it very sincerely, we fully appreciate the sacrifices you have made so that you can participate in this case," said Judge Horne.

When the jury will emerge from behind closed doors with a decision is anybody's guess.

"You should not read into it if it should take them more than a day or more than two days. With this long of a trial the number of witnesses and exhibits in the hundreds, it would not be surprising if it took them several days to go over the evidence and make a decision on what they think," said Kroner.

There are three possible outcomes from the jury deliberation.