Tiffanie Irwin, 29, is now one of eight people to be indicted over the death of Lucas Leonard in October.
The 19 year old was beaten to death over 10 hours, after he'd expressed a desire to leave the Word of Life Church in Chadwicks, New York.
The other people accused of second-degree murder, kidnap and gang assault include the victim's father Bruce Leonard, 65.
Pastor Tiffanie Irwin's mother, Traci Irwin, faces the same charges, as does David Morey, 26, Linda Morey, 54, and Joseph Irwin, 26, who were all members of the church; and Sarah Ferguson, 33, the half-sister of Lucas Leonard.
Lucas' brother, 17 year old Christopher Leonard, was also beaten but survived the assault.
During a preliminary hearing in October, he testified that he and his brother had been wounded by an electrical cord, which had been folded into a whip.
Their mother Deborah Leonard, 59, is due to appear in Oneida County Court on December 2 to face separate charges of first-degree assault against Lucas and second-degree assault in Christopher's beating.
The Word of Life Church is located in Chadwicks, New York, and has existed for around 30 years in a rural part of New Hartford, a town of 22,000 people about 50 miles from Syracuse.
It once had 40 or more members but now counts closer to 20, New Hartford police Chief Michael Inserra said after the attack.
A former member of the church has been quoted as saying there was a climate of fear, which was instilled by the church's founder, Jerry Irwin.