Deir al-Qamar had already been captured by Druze forces and its residents had consistently appealed for protection from their friends among the local Druze and from the Ottoman authorities.
Nonetheless, following their decisive victory at Zahle, the Druze renewed their assault against Deir al-Qamar on 20 June.
In the weeks prior, some of the town's wealthier residents managed to leave for Beirut or gained Sa'id Jumblatt's protection in Moukhtara.
However, thousands of Christians remained in Deir al-Qamar and the Druze militiamen were preventing many from leaving.
As Druze fighters moved in on the town, ostensibly guarding homes and shops, they proceeded to loot many buildings that had been abandoned by their patrons.
The Christian residents did not put up armed resistance against the Druze fighters, and sometime before 20 June the Christians had been disarmed either at the counsel of the district governor Mustafa Shukri Effendi or an Ottoman general from the Beirut garrison named Tahir Pasha.
The Ottomans' advice to the Christians regarding disarmament was that it would help in not provoking the Druze.

On the evening of 19 June, a Christian resident and a priest were killed outside the government house in Deir al-Qamar, where thousands of residents had begun taking refuge.
Hundreds of others took shelter in the abandoned Ottoman barracks at Beit ed-Dine or the district governor's residence.
Meanwhile, Druze fighters from Moukhtara, Baakline, Ain al-Tineh, Arqub district, Manasif district, Boutmeh, Jdaideh, Shahahir, and Ammatour were streaming into Deir al-Qamar from several directions.
At least part of these forces were commanded by Sheikh Qasim Imad.
The roughly 4,000 Ottoman troops stationed in Deir al-Qamar did not stop the incoming Druzes.
On the morning of 20 June, the Druzes assaulted the government house and proceeded to kill the males taking refuge in it, all of whom were unarmed.
European consuls who witnessed the killings or their aftermath reported that many women were assaulted as well in an unprecedented manner.
Afterwards, the Druzes plundered Deir al-Qamar, which was well known for being wealthy.
Unlike in Zahle, the Druzes looted large quantities of horses, livestock, jewellery and other goods.
Large parts of the town were burned down.
Other Christians were killed throughout Deir al-Qamar.

Nearby Beit ed-Dine and its countryside was also sacked.
The plunder in Deir al-Qamar ended on 23 June, after intervention by Sa'id Jumblatt, Bashir Nakad, sheikhs from the Hamada clan, and an Ottoman colonel.
By the end of the fighting, much of Deir al-Qamar, which was the most prosperous town of the predominantly Druze Chouf district, was in ruins, and corpses, some mutilated, were left throughout the town's streets, markets, houses and Ottoman government buildings and military installations.
Between 1,200 and 2,200 Christians had been killed in the onslaught and many more had fled.
By October 1860, Deir al-Qamar's population which had been roughly 10,000 before the conflict, had been reduced to 400.
According to Fawaz, the ceasefire negotiated between by the Druze sheikhs and the authorities marked the "end to the most violent phase of the civil war" in Mount Lebanon.
Deir al-Qamar had already been captured by Druze forces and its residents had consistently appealed for protection from their friends among the local Druze and from the Ottoman authorities. Nonetheless, following their decisive victory at Zahle, the Druze renewed their assault against Deir al-Qamar on 20 June. In the weeks prior, some of the town's wealthier residents managed to leave for Beirut or gained Sa'id Jumblatt's protection in Moukhtara. However, thousands of Christians remained in Deir al-Qamar and the Druze militiamen were preventing many from leaving. As Druze fighters moved in on the town, ostensibly guarding homes and shops, they proceeded to loot many buildings that had been abandoned by their patrons. The Christian residents did not put up armed resistance against the Druze fighters, and sometime before 20 June the Christians had been disarmed either at the counsel of the district governor Mustafa Shukri Effendi or an Ottoman general from the Beirut garrison named Tahir Pasha. The Ottomans' advice to the Christians regarding disarmament was that it would help in not provoking the Druze.
On the evening of 19 June, a Christian resident and a priest were killed outside the government house in Deir al-Qamar, where thousands of residents had begun taking refuge. Hundreds of others took shelter in the abandoned Ottoman barracks at Beit ed-Dine or the district governor's residence. Meanwhile, Druze fighters from Moukhtara, Baakline, Ain al-Tineh, Arqub district, Manasif district, Boutmeh, Jdaideh, Shahahir, and Ammatour were streaming into Deir al-Qamar from several directions. At least part of these forces were commanded by Sheikh Qasim Imad. The roughly 4,000 Ottoman troops stationed in Deir al-Qamar did not stop the incoming Druzes. On the morning of 20 June, the Druzes assaulted the government house and proceeded to kill the males taking refuge in it, all of whom were unarmed. European consuls who witnessed the killings or their aftermath reported that many women were assaulted as well in an unprecedented manner. Afterwards, the Druzes plundered Deir al-Qamar, which was well known for being wealthy. Unlike in Zahle, the Druzes looted large quantities of horses, livestock, jewellery and other goods. Large parts of the town were burned down. Other Christians were killed throughout Deir al-Qamar.
Nearby Beit ed-Dine and its countryside was also sacked. The plunder in Deir al-Qamar ended on 23 June, after intervention by Sa'id Jumblatt, Bashir Nakad, sheikhs from the Hamada clan, and an Ottoman colonel. By the end of the fighting, much of Deir al-Qamar, which was the most prosperous town of the predominantly Druze Chouf district, was in ruins, and corpses, some mutilated, were left throughout the town's streets, markets, houses and Ottoman government buildings and military installations. Between 1,200 and 2,200 Christians had been killed in the onslaught and many more had fled. By October 1860, Deir al-Qamar's population which had been roughly 10,000 before the conflict, had been reduced to 400. According to Fawaz, the ceasefire negotiated between by the Druze sheikhs and the authorities marked the "end to the most violent phase of the civil war" in Mount Lebanon.
1860 Mount Lebanon civil war