The topic of the shameful slander of Aisha RA is up for discussion by Shaykh Yasir Qadhi in this interesting lecture.
The story of the Ifk or slander is explicitly cited in a hadith from Al Bukhari that is elaborately long and is referenced in first person by Aisha RA herself. It involves a lost necklace, a sahaba by the name of Safwan bin Muattal RA and the rumour inflicter - Abdullah ibn Ubayy ibn Salul. What transpired in that event? Why did this slander go beyond control?
Do listen intently to fully comprehend the actuality of the incident and consequently, put all false stories to rest.