Police in Pakistan have arrested four people who allegedly killed an 18-year-old woman in the purported name of honor after a picture of her sitting with a boyfriend went viral on social media. Authorities said Thursday that the woman’s father and three other men were detained days after the slaying in Kohistan, a district of Khyber Pakhtunkhwa province bordering Afghanistan. The local police chief says the four arrested men apparently killed the woman on orders from village elders, who thought she had brought shame to her family by posing for pictures with a boy. So-called honor killings are a significant issue in Pakistan, where close relatives take the lives of hundreds of women each year.