Aid to the Church in Need reported the news of the death of two women, knifed to death by gunmen who broke into their home.
Lamyaa Sabih and her sister Walaa died from the injuries sustained during the attack, which took place in the early hours of Wednesday in the residential zone of Alqahira in Mosul.
Their mother, who lived with them, was also knifed. She is now in serious condition.
When police arrived to the home, a bomb planted by the attackers exploded, killing three policemen and damaging the Sabih family home. So far, no one has claimed responsibility for the attack.
Both sisters were in their 40s and were known to be devote Syro-Catholics. Lamyaa was single. Walaa was married and had two adolescent children.
This event, Aid to the Church in Need affirmed, brought panic to the Christian community of Mosul. They said Christians, as well as other minorities, believe that the twin homicides cast doubt on government efforts to promote security with a greater police presence in response to last month's campaign of violence and intimidation against Christians.
Those attacks moved more than 2,000 families, about 12,000 people, to flee the city. Vatican spokesman Jesuit Father Federico Lombardi had described that campaign as a systematic targeting of Christians with house-by-house, "leave or die" threats.
Friar Bashar Warda, who supervises the ACN emergency relief programs for those who have left Mosul, said in an interview with the charity group that the slaying of the two sisters is having a "dramatic" effect on the faithful, who now fear a new wave of violence against them.
"It is clear that many are thinking of leaving Mosul again," he affirmed. "The government says the city is now safe, and suddenly an attack like this happens."
Christian Iraqi leaders said that the attack shows the government is failing to keep its promise to bring peace and security to the church communities, and they ask the West to intervene to defend not just Christians, but all Iraqi minorities.
"The government is trying to deceive the outside world, making them believe that they are acting correctly and that Christians are safe," said one local Catholic leader. "In reality, the situation is still very challenging."