The massacre lasted from the evening of Thursday 16 September to the morning of Saturday 18 September (Traboulsi gives 15-17, Hanf 17-18). The killers were militiamen of the Lebanese Forces' security service under Elie Hobeika, together with men of Saad Haddad's South Lebanon militia. The Israeli army, which controlled the area after entering West Beirut on 15 September, let them into the camps, lit the camps with flares at night and watched from command posts nearby. Israel's Kahan Commission, published on 7 February 1983, held the Phalangists directly responsible and found Defence Minister Ariel Sharon personally responsible, recommending his removal; it also attributed indirect responsibility to other Israeli political and military leaders. Estimates of the dead range from about 460-800 to 3,500; Bayan Nuwayhed al-Hout's survey found victims of twelve nationalities, about half Palestinian and more than a quarter Lebanese.

Amine Gemayel was elected in the same Fayadiyeh barracks as his brother, with 77 votes of the 80 deputies present (Hanf). On the evening of 20 September Israeli ministers Yitzhak Shamir and Ariel Sharon had met him secretly at Dbayeh (Ménargues).

The attempt on Walid Jumblatt left him only slightly hurt. Hanf sees it as one more spur to Druze mobilisation, which put about 30,000 men under arms.

Robert Fisk recounts that Defence Secretary Weinberger proposed an award for Charles Johnson, a Marine captain who in January 1983 stopped an Israeli tank unit entering the Marine sector off the old Sidon road by climbing onto the lead tank and pointing his pistol at its commander.

Lebanese and Israeli delegates met in turn at Khalde, in a repaired beach hotel, and at Kiryat Shmona. De Clerck and Malsagne count 37 meetings over 138 days, from December 1982 to May 1983.

Early in 1983 the Eighth Brigade went into all of Beirut, the east included, under a plan to collect light arms in the city and clear heavy weapons and gunmen from Greater Beirut. The Lebanese Forces resisted, then on 1 March 1983 agreed to return East Beirut and the port's fifth basin to the state.

Counts differ: Hanf has 64 for, 2 against and 4 abstentions among 70 deputies present (40 of 50 Christian and 24 of 41 Muslim members in favour); Traboulsi has 65 for, 2 against and 4 abstentions; Fisk puts the vote on 15 June. Traboulsi says the government formally renounced the agreement on 5 March 1984, Amine Gemayel never having signed it.

Massacres were committed on both sides: Druze fighters killed Christians at Bmaryam, Bhamdoun, Ma'asir al-Chouf and many other villages, and Lebanese Forces fighters killed Druze at Kfarmatta and in villages on their line of retreat. For September to December 1983 de Clerck and Malsagne give more than 1,500 Christians and 207 Druze massacred, 324 PSP and 368 Lebanese Forces fighters dead, and over 163,000 Christians driven from the region. Traboulsi gives 62 villages destroyed, Hanf about sixty.

The Lebanese army had under 24 hours' warning, Fisk writes, before Israeli troops began leaving Aley and the Chouf on the evening of 3 September; by the morning of the 4th they had gone. De Clerck and Malsagne count more than 10,000 Christians from over 60 villages sheltering in Deir el-Qamar.