Editor's Note: The above video is from April 2019.

PORTLAND, Ore. -- Defense lawyers for romance novelist Nancy Crampton Brophy argued murder charges should be thrown out because police and prosecutors mishandled key evidence and botched the investigation.

“The defense efforts have been frustrated again and again and again by the state’s loss, destruction or failure to preserve key evidence in the case,” wrote Lisa Maxfield, defense lawyer for Crampton Brophy in court documents filed this week.

Crampton Brophy is awaiting trial for the murder of her husband Daniel Brophy, 63, a longtime instructor at the Oregon Culinary Institute. He was found gunned down at the cooking school in Southwest Portland on June 2, 2017.

RELATED: Romance novelist drove by Oregon Culinary Institute shortly before husband's body was found, court docs say

There were no arrests immediately following the early morning killing, although detectives quickly turned their focus to the victim’s wife, who authored the novel “The Wrong Husband” and a 2011 essay titled, “How to Murder Your Husband.”

A probable cause affidavit stated Crampton Brophy was caught on surveillance video driving her Toyota minivan near the culinary school around the time of the murder.

In newly filed court documents, the defense claimed investigators failed to preserve DNA samples from shell casings found at the murder scene, didn’t swab a handgun correctly and vacuumed up key evidence.

The defense explained it set out to prove the proximity of the shooter to Brophy when he was killed.

“The killer took only two shots, both of which were near-perfect shots to the heart,” wrote Maxfield.

The defense team said a criminalist didn’t find any gunshot residue on the front of the victim’s shirt but did find a significant amount on a HEPA filter found packaged with the shirt- suggesting the residue had been vacuumed out. The defense argued gunshot residue patterns could have excluded Crampton Brophy as the shooter, but they were destroyed.

The defense also argued a search warrant for Crampton Brophy’s home, van and iPhone was invalid because it was overly broad, and investigators withheld information from the judge.

“The warrant offered police a blank check to rummage through Ms. Crampton Brophy’s digital property, documents and other possessions indiscriminately,” wrote Maxfield.

RELATED: Romance novelist drove by Oregon Culinary Institute shortly before husband's body was found, court docs say

In an affidavit justifying the search warrant, a Portland police detective described a 2011 article titled, “10 Ways to Cover Up a Murder,” found on the couple’s shared iCloud account.

The defense explained, the detective failed to mention 178 other bookmarks were also saved on the account including, “10 Writing Mistakes that Kill Your First Chapter,” “33 Super-Cool Popsicles to Make This Summer,” and “5 Plotting Methods for Fiction.”

Defense lawyers also contend the detective left out key facts in suggesting that Crampton Brophy killed her husband for money. The detective wrote Crampton Brophy is the beneficiary of life insurance policies valued at roughly $350,000.

The defense argued the detective failed to tell the judge Crampton Brophy had also purchased numerous insurance policies on her own life, with her husband as the beneficiary.