MERIDIAN - Police say a 53-year-old woman who died after falling off her horse last month was likely murdered by her husband.

On Wednesday, officials served a search warrant at the couple's Idaho home and inside, about two hours later, authorities found Mark Newby, 46, dead of a self-inflicted gunshot wound, according to the Ada County Coroner's office.

It was reported last month that 53-year-old Sue Newby and her husband were riding in the Eagle Foothills near a cliff when the horse reportedly got its hoof stuck and threw Newby 100 feet into the canyon.

She died at the scene but officials say it was apparently never an accident.

"We could have charged Mark Newby with the death of his wife Sue, for pushing her off of that cliff," said Gary Raney, Ada County Sheriff.

Officials say many pieces of the puzzle didn't fit so they began investigating and found what they call a lot of complicated circumstantial evidence.

Jim Barker, a neighbor of the Newbys, said the couple had talked to him about going riding with them but the horse ride never happened. He knows the area in the Eagle foothills where she fell to her death.

He said he was suspicious from the start.

"When I heard that there had been a warrant, I started to put it together," Barker said.

Police say Newby went to another woman who he was having an intimate relationship with and told her about his wife's death. When this woman commented about how upset he must be, he apparently said that he wasn't especially upset.

Authorities said there were very suspicious financial arrangements Newby made before his wife's death and the sheriff said his behavior after his wife's death was also very puzzling.

"This was a tragic death of Sue," Raney said.

The sheriff said had Newby not committed suicide, officials would have likely charged him with murder either today or in the coming days.

According to Ada County court documents Newby pleaded guilty to a disturbing the peace charge in 2004, which was originally battery.

Prosecutors lowered the charge to disturbing the peace when Newby agreed to a domestic violence evaluation. He served 95 days in jail, and was on unsupervised probation from June 2005 to February 2006.