A man who witnessed his sister murdered in an honor killing by their father and brothers as a child has murdered multiple members of his family in a revenge killing.

The killer, identified only as Bahram, was just 12 years old when he witnessed the brutal murder of his sister in the hands of their father and brothers, leaving him with serious mental trauma.

On Saturday, following a verbal altercation, Bahram, 22, a teacher, stormed his family's home armed with a Kalashnikov rifle, killing 12 people before being killed by police.

Among the dead were the parents, three brothers, two sisters, one sister-in-law, and four nephews. Additionally, three neighbors sustained injuries during the altercation but survived.

The incident sheds light on a broader issue of honor killings in Iran. Recent reports from human rights organizations have highlighted the trend, with 13 women falling victim to such violence across various cities between September 29 and October 16. 

The exact number of such murders remains undisclosed, obscured by secrecy and a lack of transparency within the regime. Previous estimates suggest an annual range of 375 to 450 such killings, indicating a likely higher toll due to underreporting data.