BEIRUT (AP) — The family of a Hezbollah member convicted in the 2005 assassination of former Lebanese Prime Minister Rafik Hariri described Thursday the guilty verdict handed down by a U.N.-backed tribunal as a “grave injustice.”

The comment was the first by relatives of Salim Ayyash, who was found guilty as a co-conspirator in five charges linked to his involvement in the suicide truck bombing that killed Hariri and 21 others in a huge blast 15 years ago. It was released in a statement distributed by Hezbollah.

The Shiite Muslim group has consistently denied involvement in Hariri's killing, calling it a conspiracy against it and has vowed not to hand over any suspects. Ayyash, 56, has been at large and is not likely to serve time. A hearing will be held at a later date to determine his sentence.

In its verdict Aug. 18, the Special Tribunal for Lebanon convicted Ayyash and acquitted three others of involvement in the assassination, which sent shock waves through the Middle East. The tribunal’s judges also said there was no evidence the leadership of Hezbollah and Syria were involved in the attack.

Ayyash's family, in the statement issued Thursday, said Ayyash, who hails from the southern Lebanese village of Harouf, was a patriot who served in the Civil Defense and was in Saudi Arabia performing a hajj pilgrimage when the crime occurred.

“All of this refutes this accusation and emphasizes its injustice, weakness and invalidity of the conviction,” it said.