SOFIA (Reuters) - A Bulgarian court on Tuesday sentenced radical imam Ahmed Mussa and 13 other Bulgarians for propagating religious hatred and incitement to war in their support for the Islamic State militant group.

The trial against Mussa and his supporters began in 2016 following an investigation into suspected sympathizers of Islamic State in southern Bulgaria.

Mussa, already serving four years in jail for spreading radical Islam, was sentenced by the regional court in the southern city of Pazardzhik to 8-and-1/2 years.

His supporters, men from the southern towns of Plovdiv, Pazardzhik and Asenovgrad, received jail sentences of between one and 3-and-1/2 years. The only woman in the group got a suspended sentence.

In late 2014, following raids in more than 40 homes and a mosque in southern Bulgaria, investigators discovered a large number of shirts, hats, flags and banners with the logo of the Islamic State.

Prosecutors have said that Mussa, a former Christian of Roma origin who converted to Islam in 2000 while working in Vienna, had preached surrounded by the Islamic State flags. His group had attempted to recruit fighters for the militant group which had at the time seized parts of Syria and Iraq.

Bulgaria supported the U.S.-led coalition fighting Islamic State but has not taken an active military role.

Muslims make up about 12 percent of Bulgaria’s 7 million population and most belong to a centuries-old community, largely ethnic Turks.