ISTANBUL (Reuters) - A Turkish court sentenced three people to multiple life sentences on Wednesday in connection with a bombing that killed 12 German tourists in Istanbul two years ago.

A suicide bomber, Saudi-born Syrian Nabil Fadli, killed the tourists when he blew himself up in Sultanahmet, Istanbul’s historic heart, on Jan. 12, 2016. Turkish authorities blamed Islamic State for the attack.

Two Syrians, Atala el-Hasan el-Mayyup and Fevzi Muhammed Ali, and a Turkish man, Halil Dervis, were found guilty of aiding murder, trying to overthrow the government and constitution, membership of a terrorist organization and committing crimes in the name of an armed terrorist organization.

They were each given 12 aggravated life sentences, 12 terms of 16 years and 16 eight-year terms for the injuries caused. They were also given nine years for transporting explosives from Syria, for a total of 329 years each on top of the multiple life sentences.

A lawyer for two of the convicted, Atanur Demir, said the investigation into the case was not thorough and that he would challenge the verdict.

“I am of the opinion that this verdict will be overturned by the appeals court,” he said.

One other defendant received a six-year sentence for membership in a terrorist organization. Unlike the others, he was released pending appeal. Eighteen defendants were found not guilty and four others remain at large.

The bomber, Fadli, was born in Saudi Arabia in 1988 where his father was teaching. He fought in the ranks of Islamic State in Syria and was at one stage captured and tortured, before entering Turkey a few weeks before the attack, officials said.

Fadli registered as a refugee with authorities in Istanbul in early January, 2016, before blowing himself up among groups of tourists in Sultanahmet Square near the Blue Mosque and Hagia Sophia, striking at the heart of Turkey’s tourism industry.