Paratroopers laid siege to a home in Jenin on Thursday, setting off a fierce gun battle that left St.-Sgt. Ido Shapira, 20, dead and forced the surrender of six terrorists who directed five suicide bombings which killed 22 Israelis last year. The IDF revealed on Friday that Shapira was actually killed by "friendly fire." The initial findings of a committee set up by OC Central Command Yair Naveh to investigate the death were presented to Shapira's family. The army said it viewed the incident as "unfortunate and regretful," and that the IDF would continue to investigate the case until they uncovered exactly what happened. In the first major operation in the West Bank since Tuesday's raid on a Jericho prison, IDF troops entered Jenin overnight Wednesday in hot pursuit of six Islamic Jihad and Tanzim terrorists suspected of directing the local terror infrastructure. The paratroopers surrounded the home in which the fugitives were holed up and demanded their surrender. A fierce gun battle raged throughout the operation, and Shapira was fatally wounded by gunfire. A helicopter was dispatched to evacuate him to a hospital but he died at the scene. The army said it was waiting for the results from ballistic and forensic tests to determine exactly how he died. "It was a complicated operation," a Central Command officer said. "There were exchanges of fire, and we have not ruled out the possibility that he was shot by IDF troops." Daniella Shapira - Ido's mother - said her son loved his service as a combat officer in the Paratroop Brigade. "He believed that his service was significant, and he used to tell me that he didn't care if he would die," she said. "He was a happy person." Shapira saw his parents for the last time on Wednesday when he went home to Haifa. He was supposed to travel to the US this summer to work as a Jewish Agency emissary at a summer camp. "Ido came to us with a dream to make an educational difference," the Jewish Agency said in a statement. "We were privileged to know a wonderful and modest person. Ido, with his happiness for life and integrity, tried to ensure the future of the Jewish people." Searching the Jenin house, troops found two Kalashnikov rifles, two hand grenades and a pair of pistols. The army claimed that the six wanted men were in the midst of planning attacks. Previous attacks by the cell last year included: â€¢ The February bombing of the Stage nightclub in Tel Aviv in which five people were killed. â€¢ The July bombing at the Hasharon Mall in Netanya in which five were killed. â€¢ The August bombing in the Hadera market in which six were killed. â€¢ The December bombing at the Netanya mall in which five were killed. In December, another suicide attack directed by the cell was thwarted after IDF troops stationed near Tulkarm stopped two bombers dispatched by the cell and on their way to Rosh Ha'ayin. The bombers, however, detonated their explosive belts and killed Lt. Uri Binamo. The Jenin raid was part of an operation launched at the beginning of the week with the aim of demolishing the Islamic Jihad terror infrastructure in the city. Meanwhile Thursday, two security guards, one from Petah Tikva and one from Ariel, were wounded in a driveby shooting at the Hawara checkpoint south of Nablus. One of the guards was wounded in the eye and both were taken to the Rabin Medical Center's Beilinson Campus in Petah Tikva. Later in the day, a soldier and three border policemen were lightly wounded by rocks hurled at them by an angry mob in a village south of Ramallah.