(NewsNation) — After a hiker was found dead in the woods with a gunshot wound last summer, a sheriff’s office in Washington told the victim’s family he was either stabbed by a stick or had a heart attack. Now, the man’s family has filed a $20 million claim over the reportedly botched investigation.

Aron Christensen, 49, and his four-month-old puppy Buzzo were fatally shot last August while on a hike near Walupt Lake in central Washington.

Officials with the Lewis County Sheriff’s Office initially thought the Oregon music teacher died after having a heart attack and falling on a stick. But Christensen’s family believes investigators dismissed their loved one had a gunshot wound to his chest.

Lewis County Prosecuting Attorney Jonathan Meyer acknowledged multiple issues with the case in a letter to a detective, writing: “The responding deputy made an obvious error when indicating detectives were not needed to respond to the report of a gunshot victim. The error was compounded when his immediate supervisor endorsed the idea.”

According to NewsNation affiliate KOIN, Meyer announced in April that two suspects in the case would not face charges.

Now nearly a year later after the Portland hiker’s death, his family is urging the state of Washington to take over the investigation.

“Our mission is to make sure that Aron’s death gets a full and fair investigation,” the hiker’s brother, Corey Christensen, told KOIN. “The prosecutor himself stated that has not happened. So, we’re asking the Lewis County prosecutor Jonathan Meyer, or Governor Inslee to refer the matter over to the Washington State Attorney General. And we can’t ever know what happened if the investigation is not concluded with due care, so that’s kind of our main goal.”

Aron Christensen’s estate also filed a tort claim for $20 million connected to the death investigation.