In May 1999, a Yemeni court sentenced three of the kidnappers, Zein al-Abideen al-Mehdar, the self-proclaimed leader of the group, Abdullah Saleh al-Junaidy and Saleh Abu Huraira, to death for their part in the abduction and killing of the western tourists. A fourth defendant, Ahmed Mohammed Atif, was sentenced to 20 years in jail and a fifth was acquitted, as were nine others tried in absentia.

After the verdict was read, al-Mehdar called on the Aden-Abyan Islamic Army to resume its holy struggle against the West. At the end of the month, the Aden-Abyan Islamic Army issued a statement threatening to kill foreigners if the government of Yemen carried out the death sentence against its leader and two of its members. The statement was apparently sent to the media through Abu Hamza's Supporters of Sharia organization. The statement said: "If negotiations fail, all foreigners in Yemen from Western ambassadors, experts and doctors to tourists have to leave Yemen. The Aden-Abyan Islamic Army will not kidnap them but will kill them.... We saw we need to warn the foreigners." In July, Zein al-Abideen al-Mehdar told an Appeals court he would order the killings of state officials if the court did not rule according to the principles of Islamic law.

In London, Abu Hamza al-Masri said that supporters of the militants must take revenge if the executions were carried out. He reportedly told an Arab newspaper in London that anyone who "contributes" to carrying out the sentence was a "legitimate target" and was quoted as saying: "I consider anybody who contributes to the killing of Mehdar as a legitimate target."

At this writing, al-Mehdar's death sentence is on appeal and the 10 bombing suspects were convicted and sentenced to up to seven years in prison