The Bahai faith to which Dr David Kelly had converted could hold a clue to his frame of mind before he committed suicide, a friend believes.
Dr Kelly "drew come consolation" from Bahai teachings
The Hutton inquiry is to hear on Tuesday about the teachings of the faith and what effect it may have had on Dr Kelly.
Dr Kelly converted to the religion - which follows the teachings of 19th century Iranian nobleman Baha'u'llah, and seeks to eliminate conflicts between faiths - about four years ago.
Manoocher Samii, a friend of Dr Kelly's and member of the same community, believes the religion did shape the scientist's thoughts in some ways.
"The Bahai writings teach us to have a very world-embracing vision, if you like," he told BBC Radio 4's Today programme.
"In fact, Baha'u'llah said let your vision be world-embracing, and not confined to your own self.
"And I'm sure that David Kelly, somebody who obviously had an interest in the world, and tried to create a safer world, perhaps drew some consolation from this."
Mr Samii said the faith was "quite important" to Dr Kelly, who received an e-mail of its teachings once a day.
"He drew a lot of spiritual sustenance from the meetings that he came to, and he shared with me sometimes quotes he would read from the writings and how much they would mean to him.
"He told me once that he can't actually start his day without reading something, because that would then shape his day."
Mr Samii said the religion, like many others, stressed the importance of absolute honesty and truthfulness - but said Dr Kelly should not have been unduly affected by this.
"It is quite serious in a sense, the issue of back-biting, of lying, of always being honest, of having a trustworthy character.
THE BAHAI FAITH
One of the youngest of the world's major religions
Founded by Baha'u'llah in Iran in the 19th century
About five million followers in 200 countries, 6,000 in the UK
Based on the unity of God, of all religions and of humanity
No clergy - leaders elected
Believes humans have a soul which will last forever
One of holiest sites is Shrine of the Bab in Haifa, Israel (above)
"Having said that, we are taught as Bahais not to judge one another, because at the end of the day it's only God who can judge you.
"So I don't think David should have been particularly disturbed by the thought of having to be always honest or anything like that."
He also said Dr Kelly's faith was extremely unlikely to have encouraged the scientist to kill himself.
"The Bahai faith does not condone suicide. If anything, suicide is not allowed.
"However, we know from all religions that God is all-forgiving, God is all-merciful... we are not in place to judge other people's actions."
Mr Samii said nobody really knew how Dr Kelly was feeling, or the strain that he was under.
"We hear from other people the strain that he was under, but if we have not experienced that strain ourselves, if we have not been there ourselves, then we would not really know the frame of mind that he was in.
Mr Kelly's widow Janice has described his feelings of despair
"And as a result it's not fair for us to judge him."
The inquiry will be told about the Bahai faith from Barney Leith, secretary of the UK National Spiritual Assembly of Bahais, and another friend of Dr Kelly.
A psychiatrist will also give evidence to the inquiry on Tuesday about Dr Kelly's state of mind.
Dr Kelly died after being named as the possible source for the BBC story about claims the government "sexed up" the intelligence case against Iraq in last September's dossier.
On Monday Dr Kelly's widow Janice told of his decline into despair as pressure mounted on him in the wake of the story.