What sort of suspicion is allowed. Sahih al-Bukhari 6067
Arabic hadith text
حَدَّثَنَا سَعِيدُ بْنُ عُفَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، قَالَتْ قَالَ النَّبِيُّ صلى الله عليه وسلم "مَا أَظُنُّ فُلاَنًا وَفُلاَنًا يَعْرِفَانِ مِنْ دِينِنَا شَيْئًا ". قَالَ اللَّيْثُ كَانَا رَجُلَيْنِ مِنَ الْمُنَافِقِينَ.
Translation
Narrated `Aisha
The Prophet (ﷺ) said, "I do not think that so-and-so and so-and-so know anything of our religion." (And Al-Laith said, "These two persons were among the hypocrites.")