The man has been identified as 30-year-old Satar and belongs to Aqcha district who was initially arrested by the local tribal elders.
The district police chief Abdul Aziz has told RFE that the man was arrested on Saturday as he was trying to rape the 14-year-old boy.
He said the local tribal elders were looking to resolve the issue through jirga but the man detonated a hand grenade during the tribal elders meeting.
According to Aziz, at least six tribal elders and the man sustained injuries after he pulled the pin of the grenade.
Aziz further added that an investigation is underway regarding the incident and injured people have been taken to hospital for treatment.
Incidents involving rape of the children are not rare in Afghanistan as the sexual abuse and rape of children have been rampant in Afghanistan, specifically in northern parts of the country.