An attempted coup d'etat by Brigadier General Mane against the government of President Vieira in June 1998 led to a conflict that killed thousands as Vieira - backed by neighbouring states - attempted to re-take the country. A national unity government was established in an agreement signed in November 1998, but fighting continued until Vieira was deposed in May 1999. Only months before the coup attempt, Brig. Gen. Mane was suspended on grounds of a dereliction of duty following the discovery of a weapons cache and the arrest of several army officers on charges of arming Casamance insurgents in neighbouring Senegal. Following the deposal of Vieira, it was agreed that he would stand trial on the same charges. His deposal was condemned by ECOMOG, but ECOMOG troops were nonetheless withdrawn from Guinea-Bissau. The constitution was amended to limit presidential terms to a maximum of two and the death penalty was abolished. The opposition party won the parliamentary elections held in November 1999 by a large majority.