(IDEX Online) - A former Israeli army officer has been arrested on suspicion of stealing diamonds worth more than $600,000 from a trader.He and three fellow gang members allegedly snatched the man's bag near his home in Kiryat Ata, outside Haifa, in the north of the country.They are said to have attacked him from behind and threatened him with a gun or a knife.Police believe they'd been tracking their victim's movements for several weeks and deliberately struck in a location not covered by CCTV cameras.They described the crime as having been "meticulously planned".Four unnamed men, all in their 30s, have since been arrested and remanded in custody by a court in Haifa, according the Israeli broadcaster Mako.Among them is a man described as an outstanding officer in the IDF (Israel Defense Force) who served in an elite combat unit until a few months ago. He is alleged to have headed the gang.None of the stolen gems has yet been recovered.