The England and Wales Cricket Broad (ECB) announced the end of Pietersen's association with England earlier this week, citing a need for a new "team ethic and philosophy" after the 5-0 Test series defeat in Australia.
The ECB is yet to fully explain its reasons for deciding to jettison Pietersen, but Strauss believes it was the inevitable consequence of a breakdown in trust.
"Without trust, the team environment is stillborn," he wrote in British newspaper the Sunday Times.
"The media have been searching for a 'smoking gun'. Everyone is looking for disciplinary problems, bust-ups and character clashes, but they are looking for the wrong thing.
"The smoking gun is the total absence of trust."
Strauss identified Pietersen's dismissal as England captain five years ago as the beginning of the breakdown.
He also said that efforts to reintegrate the South Africa-born batsman into the team after he was found to have sent derogatory text messages about Strauss to opposition players were "a little like marriage counselling".
"His relationship with English cricket has been like an illicit affair. Full of thrills and excitement, but destined to end in tears.
