Witness John Gregory told the High Court in Glasgow that 46-year-old William Kean was covered in blood and his hands and face were covered in scratches.
Kean from Blairgowrie, denies murdering Mrs Methven at her cottage at Forteviot, Perthshire, on February 20, this year.
At first Mr Gregory, 64, who is Kean's brother-in-law, told the jury he thought Kean had fallen into a prickly bush.
But he told prosecutor Alex Prentice that he then noticed a cut on Kean's throat near the windpipe.
He was asked to describe this and said: "It had been cut across and vertically. The amount of blood led me to believe it had been a substantial cut."
Mr Gregory, of Coupar Angus, said he had driven to the village of Woodside around 3pm on March 19 after receiving a call from Kean who was complaining of having chest pains.
He said when he first arrived at the house, where he thought Kean was doing gardening work, he saw him in his rear-view mirror and he was uninjured.
Kean then appeared about 10 minutes later covered in blood, got into Mr Gregory's car and was driven to Perth Royal Hospital, the court heard.
Mr Prentice asked what opinion he had formed of the injuries and Mr Gregory said: "I thought he had tried to take his own life."
Under cross-examination by defence QC Brian McConnachie the court heard Kean phoned Mr Gregory the following day.
In that call the accused said: "I'm sorry. I was trying to do away with myself. The business was getting the better of me."
When he was asked by Mr Gregory what business he was referring to he said: "Scotbiz."
This was an internet company set up by Kean, who also ran a car-valeting business, which was not doing well.
However, the court later heard that in hospital the accused claimed the injuries had been inflicted by someone else.
Earlier the jury heard Mrs Methven may have fought for her life with her attacker.
Pathologist Dr Helen Brownlow said Mrs Methven died for brain injuries and blunt force trauma to her head.
Mrs Methven's two forearms were also broken with the bone piercing the skin. Dr Brownlow was asked if this could have been defensive injuries caused by Mrs Methven putting her arms up to her head as she was struck and Dr Brownlow said: "It's possible."
Dr Brownlow said that at least 11 blows landed on Mrs Methven's skull which was fractured from the left ear to the right ear.
Jagged pieces of bone had gone into her brain and Dr Brownlow said she would have been unconscious after a couple of blows.
The jury of nine women and six men was shown two pictures of the horrific injuries suffered by the pensioner.
Dr Brownlow was asked if she knew what kind of weapon could have been used and said she didn't. She added that it wasn't clear if it was just one weapon that had been used.
Kean is also accused of stealing around £15,000 from her home on September 14, last year.
Kean denies the murder and has lodged a special defence blaming Mrs Methven's son, David.
He also denies attempting to pervert the course of justice between March 13 and 19 by failing to turn up at Perth Police headquarters to have his fingerprints taken for elimination purposes and repeatedly cutting his fingertips and palms to prevent police taking usable samples.
The trial continues.