Corroborated, substantiated (9)
I believe the answer is:
confirmed
I believe this is a double definition.
'corroborated' is the first definition.
('confirm' can be a synonym of 'corroborate')
'substantiated' is the second definition.
('confirm' can be a synonym of 'substantiate')
(Other definitions for confirmed that I've seen before include "Stated with assurance that something was true" , "Verified" .)