UPDATE 1/24/10 @ 7:15 p.m.
MERCERVILLE, Ohio (WSAZ) -- Was it self-defense or was it something more?

One man is dead after a shooting in Gallia County Sunday night. Now, the sheriff says he's investigating all sides of the story involving a fatal shotgun blast from a frail cancer patient.

Medicated and in chemotherapy, Ray Fillinger says he had no choice but to fire when a man he knew barged into his home Sunday afternoon.

Investigators say Fillinger's story may be true, but they need to know more before possible criminal charges are dropped or filed

"He threatened me physically and threatened to take a belt to my daughter," Fillinger said.

Fillinger says he's known Ralph Dempsey for a year and a half, but the threats from Dempsey just began recently.

Gallia County Sheriff Joe Browning says the two men knew each other through an ex-girlfriend of Fillnger's.

Fillinger says Dempsey showed up Sunday afternoon at his rural John's Creek Road home, and the threats escalated.

"He came inside," Fillinger said. "I told him to leave and quit threatening me. He said, 'I've got something for you' and reached behind his back. I raised my gun, didn't even aim and fired."

But Browning notes of a need to fully find the motive.

"There was something said between the two men that got them angry," he said.

The sheriff says an unarmed Dempsey -- shot once in the abdomen -- drove away, crashed his car and later died at the hospital.

Fillinger was brought in for questioning and then released. Meanwhile, detectives are investigating why this shooting happened.

"We're not going to rule out self-defense, but interview and check if there's more to be pursued here," Browning said.

When finished, the sheriff will present his investigation findings to a grand jury.

As mentioned, Fillinger is a cancer patient who says he has strong painkillers at home. He said Dempsey’s threats were never about drugs.

Browning says the castle laws of the right to defend property and life still require investigation if questions remain unanswered.

The Gallia County Sheriff's Department says Ralph Dempsey was the man shot. He was taken to Cabell Huntington Hospital. A nursing supervisor there tells WSAZ.com he has since died.

The man questioned for the shooting, Henry Fillinger, has not been charged.

It happened Sunday just before 5:30pm at 1781 Johns Creek Road off of State Route 218 in Guyan Township, Gallia County. Deputies were called to the home where they say they believe the two men knew each other.

Henry Fillinger is now being held for questioning. The other man is in a Huntington hospital. His name has not been released.