Informed sources, requesting anonymity, told London-based and Arabic-language Nabaa television news network that Majid Abdullah al-Adam passed away on Saturday -- ten days after security forces, armed with heavy weapons and artillery rounds, stormed into the al-Jash district of al-Qatif region onboard armored vehicles, Presstv Reported.
The sources added that the forces fired indiscriminately, inflicting damage on many houses and buildings. Adam suffered critical injuries during the raid.
Saudi regime agents also arrested Muslim preacher Ibrahim Issa al-Ismail at the time.
Eastern Province has been the scene of peaceful demonstrations since February 2011. Protesters have been demanding reforms, freedom of expression, the release of political prisoners, and an end to economic and religious discrimination against the oil-rich region.
The protests have been met with a heavy-handed crackdown by the regime, with regime forces increasing security measures across the province.
Over the past years, Riyadh has also redefined its anti-terrorism laws to target activism.
In January 2016, Saudi authorities executed Shia cleric Sheikh Nimr Baqir al-Nimr, who was an outspoken critic of the Riyadh regime. Nimr had been arrested in Qatif in 2012.