The incident happened in Upper Mission extension of Edo State.
It was gathered that the suspect joined his members to attend a funeral service of one of their colleague who recently passed away.
It was said that the suspect fired several gun shot into the air as a sign of respect for their fallen colleague when the bullets hit the victim, a 27-year-old woman who happens to be one of the mourners and a baby.
Consequently, she died on the spot while the baby is in critical condition at the hospital.
It was also gathered that the victim is a relation to the deceased vigilante whose funeral turned into an unfortunate tragedy.
The suspect said the unfortunate incident was a result of accidental discharge.
Confirming the arrest, Spokesperson of the Edo State Police Command, SP Bello Kontongs said the suspect would be charged to court for murder, adding that other vigilante members should be careful with weapons.