Hamas' minister, Said Siam, considered one of the most senior members of the Palestinian group's leadership, was killed on 15 January 2009 afternoon in an Israeli air strike on his brother's home in Gaza City. Siam, 50, is the most senior Hamas figure was killed in Operation Cast Lead so far, and is the most senior Hamas figure killed by Israel since the assassination of Dr. Abdel Aziz al-Rantisi in April 2004. The very same aerial stick, also killed Salah Adin Fuad Sha’aban Abu Sharah, a close associate of Siyam and the commander in chief of the Internal Hamas security forces. Siam was one of the most prominent Hamas leaders in Gaza, the person who built Hamas' special Executive Force in Gaza, which was the main focus of friction and dispute between the Palestinian Authority and Hamas as the Hamas government took power, and he officially led the organization's takeover of the Gaza Strip. 
Siyam as a Hamas operative simultaneous to his involvement in Hamas activities used to work at UNRWA schools in Gaza between 1980-2003. He left his job following disagreements with his employer due to his affiliation to Hamas. Siyam participates in social and ideological activity amongst the population (Da’awa). He used to work as a preacher and a volunteer imam in mosques in the Gaza Strip. Siyam was part of Hamas’ important forums and its representative at the “Follow-up Committee of the National and Islamic Forces”. Between December 2001 and April 2002 he the Hamas spokesman. Siyam was responsible for establishing Hamas’ “Al-Aqsa” radio station, which operates out of Gaza, and was also elected to the Legislative Council. Siyam was arrested 4 times between the years 1989-1992 and was among the Hamas activists deported to Lebanon in 1992.Identified as a Hamas leader, the PA’s security apparatuses also arrested him in 1995 among other measures taken by the PA to crack Hamas leadership after a series of terror attacks against Israel and the international pressure on Arafat to act against Hamas. Said Siyam as a senior Hamas operative he was also a member of the Islamic University in Gaza board of trustees together with other Hamas leaders Muhammad Hassan Shama’a (Hamas founding member) Ismail Haniyah (the current Hamas prime minister), Hamad Hassanat (Hamas founding member, and Muhammad Taha (senior Hamas leader).
Notes: http://www.palestine-info.info/ar/default.aspx?xyz=U6Qq7k%2bcOd87MDI46m9rUxJEpMO%2bi1s7Zy0gi2V7yrqjV9wyIa%2bzD8J1h8S8p62FAc5xqcZHgBLam8bRRJpBVWjJELX%2fP1yo%2fPgVWbHsqa7iFqedSRz4V9oLLNlYHcb9xsMjcRXnQpM%3d http://www.paldf.net/forum/showthread.php?t=349708 http://www.palestine-info.info/ar/default.aspx?xyz=U6Qq7k%2bcOd87MDI46m9rUxJEpMO%2bi1s72pHOzVVTJiOToJV4IdGr6izE%2bGP8iQjJNadrmw1KB%2f0oe%2beUphDopIPlbEypJ0qGNXLlByFKN0%2bHHgRC%2fKjTOmPbxyBb9S4ubQuDv6I8Fjs%3d Al-Jazeera TV, June 15. See also “The Mujaheed Sheikh - Dr. Nizar Rayyan: The Spiritual Mentor of Iz A-Din Al Qassam Brigades” at ICT web site http://www.ict.org.il/Articles/tabid/66/Articlsid/590/currentpage/1/Default.aspx Ibid. Al-Jazeera, December 18, 2005. Reuters, March 2006. The Independent, July 7, 2006. Haaretz, June 30, 2006.