A West Virginia man, who was taken into custody last week for attempting to kill his sister whorecently woke up from a two-year coma, has died.

Daniel J. Palmer III, 55, was charged with attempted murder and malicious wounding following the June 2020 assault, which left his sister Wanda “attacked, hacked, and left for dead,” the Jackson County Sheriff’s Office of West Virginia said in a press release.

Jackson County Sheriff Ross Mellinger tells PEOPLE that Palmer was transported to the Charleston Hospital Wednesday and was pronounced dead the following day.

Mellinger believes that his death was most likely due to natural causes.

Daniel and Wanda Palmer.Jackson County WV Sheriff’s Department/Facebook

Daniel and Wanda Palmer, West Virginia Woman Wakes from Two Year Coma to Name Brother as Attacker

“It was an avalanche of recurring health issues,” says Mellinger. “He generally was not a healthy man to begin with and once he got to jail his health continued to spiral downhill.”

He was in custody for seven days.

“From an investigator’s standpoint it is unfortunate we don’t get the chance to see the case through,” says Mellinger. “We turn the focus towards the victim in the case and hope she continues to get better. She has a long road ahead of her.”

Two years ago, Wanda Palmer was found “seated on the couch with her head slumped over” at her home near Cottageville, West Virginia, Mellinger says.

“There was a lot of skull and brain trauma,” he tells PEOPLE. The weapon used was likely a hatchet or machete, he says.

Mellinger says a witness saw Palmer on his sister’s porch the night before police responded to her home, but a lack of eyewitnesses, evidence and surveillance footage made the case difficult to investigate.

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Wanda Palmer, 51, spent two years hospitalized in a coma after the brutal attack.

Mellinger says he recently received a call from her long-term care facility stating she was finally able to speak with law enforcement.

“It was pretty astonishing,” he adds. “It certainly gave us the traction we needed to move forward on our end.”

Mellinger says despite Palmer’s death, Wanda was able to get “her voice back and most importantly her voice mattered,” he says. “She got her voice back and what she had to say mattered to everybody. That’s important.”

source: people.com