Sheikh 'Ali Salman, Secretary General of al-Wefaq National Islamic Society in Bahrain. He was sentenced to 4 years in prison on 16 June 2015 after an unfair trial. He is a prisoner of conscience.

Bahrain: Opposition leader Sheikh Ali Salman unlawfully convicted

Responding to the Bahraini Appeal Court verdict, overturning the acquittal of opposition leader Sheikh Ali Salman and sentencing him instead to life in prison, Amnesty International’s Middle East and North Africa Director Heba Morayef said:
“This verdict is a travesty of justice that demonstrates the Bahraini authorities’ relentless and unlawful efforts to silence any form of dissent. Sheikh Ali Salman is a prisoner of conscience who is being held solely for peacefully exercising his right to freedom of expression.
“The Bahraini authorities must immediately and unconditionally release Sheikh Ali Salman and quash his politically motivated conviction and sentence”. 
“The international community’s silence on the continued crackdown on dissent must also come to an end. Instead of ignoring criticism of Bahrain’s human rights record, the country’s political allies must use their influence to push for the release of Sheikh Ali Salman and all prisoners of conscience in Bahrain”.
Background
Sheikh Ali Salman is the Secretary General of Al-Wefaq National Islamic Society (Al-Wefaq), which was dissolved in 2016.
In 2015 he was sentenced to four years in jail, after an unfair trial, on charges relating to speeches he made in 2012 and 2014, including at the Al-Wefaq General Assembly, in which he  spoke about the opposition’s continuing determination to reach power in Bahrain, to achieve the demands of the 2011 uprising through peaceful means and to hold those responsible for committing human rights abuses to account. He also highlighted the need for equality for all Bahrainis, including the ruling family. His arrest took place a few days after he was re-elected for a fourth term as Secretary General of al-Wefaq.
In 2017, Ali Salman’s second trial began on a range of spurious intelligence-sharing charges relating to his recorded telephone conversations with the then Prime Minister and Minister of Foreign Affairs of the State of Qatar in 2011.
Sheikh Ali Salman was acquitted on 21 June 2018, but the prosecution appealed the ruling.
More: https://www.amnesty.org/en/documents/mde11/6068/2017/en/