Prayer: Does appointment as Imam prove his justice, or must it be investigated?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Does appointment as Imam prove his justice, or must it be investigated?

English:

Question #617:

Should the Imam of a masjid be selected by trustworthy scholars or appointed as the Imam of Friday prayers by the Jurist Leader, is it considered as evidence that he is ‘ādil? Or is it necessary to investigate his justice?

Answer #617:

If the appointment makes the followers certain about the imam’s justice, then it is permissible for them to follow him in prayer.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer