'Call something into question' often indicates a polite, yet skeptical attitude without directly accusing. His absence at key meetings called his commitment into question.
Pro Tip 2/3
Not Necessarily False
Questioning something doesn't mean it's false; it suggests there are doubts to be considered. The new findings call the traditional theories into question.
Pro Tip 3/3
Impacts Credibility
Using the phrase can imply that someone or something may lose credibility or trust. These allegations call his expertise into question.