An independent financial statement audit done by external auditors is the most extensive attest service provided by auditors, and it is still limited. A review of financial statements by an independent auditor is even more limited in scope.
Reviews amount to auditors looking at account balances and determining whether or not the balances look reasonable. They will perform some analytical procedures on the financial statements to further analyze the numbers. On occasion, they may ask to see some details about accounts and their balances, but this happens on a very limited basis.
As long as the auditors don’t see anything unusual or irregular, a client will generally pass the review with flying colors.
Audits are not designed to detect fraud, are not required to detect fraud, and most times do not detect fraud. Since a review is a more limited process than audits, it stands to reason that reviews by auditors will rarely (if eve) detect fraud.
The moral of the story: An accounting review is a very low level of assurance that the financial statements are accurate.