An 8-year-old girl became the third victim Monday of a North Carolina woman, Mary Ann Holder, who was involved in a bitter love triangle and who shot five children in the head on Sunday in Guilford County.

Holder wrote two letters admitting to the murders before taking her own life.

She also apologized to all the people for the pain she caused them and then shot herself inside her parked Ford Explorer after 10 a.m., investigators said on Monday.

The letter also shows that Holder was distraught about the end of her relationship with ex-boyfriend Rany Lamb.

A Guilford County sheriff's deputy, who saw Holder killing herself, said he saw the puff of smoke from the bullet that killed the 36-year-old woman.

Chief Deputy Randy Powers said Monday the 8-year-old girl died of the head injury she suffered in the shootings.

The investigators said Holder first shot her two sons, her son's girlfriend, a niece and nephew and her ex-boyfriend before killing herself Sunday morning.

Holder’s 17-year-old son, Robert Dylan Smith, was announced dead on the spot. Her 8-year-old niece, Hannaleigh Suttles, died from head injuries on Monday.

Her 17-year-old nephew, Richard Suttles, and his 15-year-old friend, Makayla Woods, were rushed to the hospital where they were placed on life support, cops said.

The teens who survived were in a critical condition.

After an argument with Lamb in a parking lot early morning on Sunday, Holder first shot Lamb in the arm, following which investigators started a manhunt for her.

Lamb immediately called his wife from his car, after the violent confrontation, and his wife then called up the police.

According to WFMY, Guilford County Sheriff B.J. Barnes said Lamb and Holder once had an affair in 2008 and that the relationship led to a lawsuit, including allegations of alienation of affection.

Barnes said that the two weapons had been recovered from the scene and that there is a possibility that the shootings had been pre-arranged.