TULSA, Oklahoma - The jury in the trial for the teen accused of stabbing his own family is hearing for the first time that a Broken Arrow police detective lost some of the evidence in the case.

Michael Bever is charged with killing his parents and 3 siblings.

Michael Bever's attorney was finally able to tell the jury about some of the mishandled evidence in this case. But prosecutors are quick to point out that the most important evidence was handled with integrity.

"I'm trying to focus on what's relevant evidence in the case," said Tulsa County DA Steve Kunzweiler. 

Since before the trial, Michael Bever's attorney Corbin Brewster has taken issue with the fact that there's mishandled evidence in this case including a hard drive that's never been found.

"I think the jury heard some interesting things about the integrity of the investigation," said Brewster. 

But Kunzweiler said it's important for the jury to realize which evidence takes priority.

"I've never seen in this case any evidence to suggest that a computer killed any one of the five people, or that a hard drive was responsible for the death of any of these people," said Kunzweiler. 

Crime Scene Investigator Jackie Smithson admitted Thursday that the hard drive is missing and even said there are some pieces of evidence that were opened and not re-sealed properly.

"These are issues the jury should hear about, consider, to understand how this evidence was collected and whether we can rely on it," Brewster said. 

Bever's biggest defense at this point remains the difference between his role in the murders and his brother Robert's role.

"Our defense is the difference between Robert and Michael. The differences between what they did," said Brewster, adding, "I think that is a very powerful image, for them to see that contrast."
Prosecutors have already called 13 witnesses and will call more Friday. 

This trial could go well into next week.