DHAKA (AFP) - Prosecutors charged the eldest son of ex-Bangladesh premier Khaleda Zia Sunday over a 2004 grenade attack that killed 20 people and injured rival and current prime minister Sheikh Hasina. Tareque Rahman, 46 and now living in London, has been indicted for abetting the attack, the country's worst political violence in decades which severely injured one of Hasina's ears, state prosecutor Syed Rezaur Rahman said. "We have pressed charges against Tareque and 29 others including a former political secretary of Zia, an ex-home minister, a leader of the country's top Islamist party and a Kashmiri militant," Rahman told AFP. "We have evidences that Tareque abetted the grenade attack. The main culprits met him at his Hawa Bhaban office, where he assured them all kinds of help for the attack. The aim was to kill Hasina." Hasina, the then main opposition party leader, was addressing a rally in central Dhaka on August 21, 2004 when the grenades went off, leaving at least 20 people dead including the wife of the country's current president. The militants belonging to the banned Harkat-ul Jihad al Islami (HuJI) were initially blamed for the attack and investigators have already pressed charges against 22 including top HuJI officials. The latest indictment brought the number of people charged over the incident to 52, Rahman said, adding half of them are hiding including the main accused, Maolana Tajuddin, who is believed to have fled to Africa. The case took a new turn in 2008 when police arrested former state minister for education, Abdus Salam Pintu, a brother of Tajuddin, and accused him of abetting and aiding militants to carry out the attack.