LA CROSSE, Wis. -- The prosecution is expected to rest its case by the end of the week. For the last week and a half, though, prosecutors have been trying to convince the jury Eric Koula killed his parents over money two years ago

Wednesday, the jury heard investigators and forensic experts analyze evidence found surrounding the deaths of Dennis and Merna Koula.

Prosecutors admit there is no physical evidence proving Eric Koula went to his parents' home on May 21, 2010 and shot them to death. But they also said that doesn't mean he didn't do it.

It was day three of questioning for lead investigator John Christopherson. The prosecution continued to press him on how he felt Koula misled law enforcement.

Christopherson said Koula, who is accused of killing his parents for money, tried to divert attention from himself by placing a note in his own mailbox that said "fixed u."

Plus, Koula denied having money problems and did not tell investigators about a $50,000 check, which he signed in his father's name, dated the day of the murders and deposited the day after.

"Did he also deny signing the check from his father?" asked La Crosse County District Attorney Tim Gruenke. "He denied signing the check and stated he knew nothing about the note that was planted in the mailbox," said Christopherson.

"Did he also deny being broke?" asked Gruenke. "Yes," said Christopherson.

Meanwhile, the defense tried to poke holes in Christopherson's claim that Koula's alibi doesn't hold up. Koula said he was at a Shopko looking at plants around the time his parents were thought to have been murdered. But he isn't on the surveillance video.

The defense said, since the surveillance camera pans back and forth, Koula might have been there without being seen.

"You never attempted to see if a person could drive up during that time period, where the camera has panned to the South, without being seen, look at the flowers briefly and leave. Correct?" said defense attorney Keith Belzer. "No, we haven't," said Christopherson.

Sherry Culhane, a DNA analyst from the state crime lab, also took the stand. She said Koula was not the primary source of DNA on any evidence found in his parents' house the day their bodies were found.

But the prosecution said that doesn't mean Koula wasn't there.

"If someone's DNA is not detected in a house, does that mean he was never there?" asked prosecutor Gary Freyberg.
"No," said Culhane.
"Does it mean the person wasn't there at the time of the crime?" asked Freyberg.
"No," said Culhane.
"Does it mean he didn't commit the crime?" asked Freyberg.
"No," said Culhane.

More than 90 items for this case were submitted to the state crime lab for DNA analysis.

Eric Koula faces life in prison if convicted.