Yaacov was born  March 20, 1920 in Baranovitz  Poland to Bracha and Shraga, a secular family, whose four children completed high-school. Yaacov completed two years at Vilnius University. He was a Beitar member, among the founders of Poland’s Etzel cells and commander of it’s eastern region. Beginning  1940 he left for Israel. In Turkey he heard about Etzel splitting and joined Yair. On arrival he was ordered to keep away from Tel-Aviv. He became a Jewish Policeman in Emek-Yizrael. Beginning  1943 he transferred to Haifa heading its branch. Following a shootout with two British detectives,transferred to Tel-Aviv, he joined Operations. In Jerusalem he participated in the attempt to assassinate High Commissioner MacMichael, in the assassination  of CID Officer Wilkin, and in  a special command course.  He  commanded the Operations branch and planned most of Lehi’s operations. Attacks on military/police units, detonating bridges,  commanding a joint attempt with Etzel to free prisoners (Jerusalem Prison) and weapon confiscations from the British camp. After Yitzhak Shamir’s arrest, he became operations chief, managing Lehi branches/departments. During this period the attack on the Haifa Railways Workshops took place, blowing up  Command Posts  at Sarona, Sarafend, Haifa CID building and destroying airplanes at Kfar-Sirkin Airport. Following  November 29, 1947, UN Partition Declaration and the attacks and murders  by Arab gangs of innocents, Lehi responded  counter-attacking the Jaffa Saraya building, the Haifa Gangs’ HQ and more. After establishment of the IDF, he joined the 8th Brigade commanding the Lehi Battalion and later, Brigade Operations  Officer. As  Lieutenant-Colonel he was Battalion commander in Reserves. Yaacov  served 10 years in Civil Defence and commanded the Dan Region. He published the book “Anonymous Soldiers” and frequently lectured. Yaacov married Hana Kruger 1945 and they had two children, Nili and Shraga. They have three grandchildren plus two great-grandchildren. He worked in the Egged bus co-operative secretariat. Before retiring 1997 he was President of a retirement homes company. In 2000 he was named Esteemed citizen of Ramat-Gan. He was chairman  of the Lehi Commemoration Committee and remains an active member. Yaacov passed  away  on January 7, 2009 and was buried at Morasha cemetery Ramat-Hasharon.