Details emerged Thursday about the investigation of engineer Dirar Abu Sisi, who according to foreign reports was abducted by Israeli forces in the Ukraine last February. The information was made public after a Be'er Sheva court lifted a comprehensive gag order on Abu Sisi's interrogation.

Sisi told investigators he helped Hamas boost its rocket capabilities, including launch and range capabilities. He said he used "mathematical equations, which improve the ability of the iron rods to withstand pressure and heat."

In 2002 Abu Sisi began working with Mohammed Def, the head of Hamas' military wing who currently tops Israel's most wanted list. The two began developing a new rocket called Albana, yet according to Abu Sisi, they were unsuccessful.

"In 2003, Hamas asked me to extend the Qassam rocket's range by up to six kilometers," Abu Sisi told the interrogators. "In 2005 they asked me again to extend the range to nine kilometers, then 15." He added that eventually he was asked to extend the range by 22, 32, 37 and 45 kilometers.

In his investigation, Abu Sisi also said he started a new academy that taught "military tactics and techniques," as well as "human resources management, time management crisis management and general administration."

Abu Sisi expressed remorse for his activities, saying he was "sorry for being part of the Muslim Brotherhood and Hamas," and for his involvement in developing rockets. When he tried to leave Hamas, he said, he was threatened that "many warriors are killed in unusual missions." He said he sent a letter to Mohammed Def asking to discontinue his involvement, but never received an answer.

According to foreign reports, Abu Sisi, formerly a high-ranking engineer at Gaza's electric company and power station, was abducted by Israeli security forces after boarding a train in the eastern Ukraine city of Kharkiv heading for Kiev, where he planned to meet a brother who has been living in Amsterdam for several years.