If we see or hear about someone else committing a sin, we should always try to ignore it. Instead of spreading it, we should hide it and keep it a secret.
It is reported that the Prophet SAW: has said:
Whosoever covers (the sins of) a Muslim, Allah covers (his sins) on the Day of Judgment. (Reported by Bukhari)
It was narrated that Abu Hurayrah (may Allah be pleased with him) said:
The Messenger of Allah (pbuh) said:
“Whoever removes a worldly hardship from a believer, Allah will remove one of the hardships of the Day of Resurrection from him. Whoever grants respite to (a debtor) who is in difficulty, Allah will grant him relief in this world and in the Hereafter. Whoever conceals (the fault of) a Muslim in this world, Allah will conceal him (his faults) in this world and in the Hereafter. Allah will help a person so long as he is helping his brother.”
Narrated by Muslim (2699)
If we find it too difficult to keep it secret, the most we are allowed to do is discuss the issue with the person, in private, and try to encourage them to stop committing the sin(s).
Allah swt has said:
The believers, men and women, are Auliyâ' (helpers, supporters, friends, protectors) of one another, they enjoin Al-Ma'rûf (i.e. Islâmic Monotheism and all that Islâm orders one to do), and they forbid (people) from Al-Munkar (i.e. polytheism and disbelief of all kinds, and all that Islâm has forbidden).
(Quran, 9: 71)
Islam teaches its followers to think well of others to maintain good relations and preserve the unity amongst the community. Hence, let us abstain from creating any conflict such as slandering and spreading fabricated news as it will not benefit the society in any way. Islam also considers such actions to be among the greatest verbal sins.
_
The Prophet s.a.w. once said: “A Muslim is the one from whose tongue and hands the Muslims are safe, and a Muhajir (Emigrant) is the one who refrains from what Allah has forbidden.” [Hadith narrated by Imam Al-Bukhari
NOTE: This excludes the evildoer who broadcasts his sins, and speaking ill of him is not regarded as backbiting.
And Allah knows best.