Dutch hold 4, search for nerve agent DUTCH police have spent three days digging up a field after receiving a tip off that sarin may have been buried there, but they have found no trace of the deadly nerve agent. Two men and two women have been arrested in the case in the southern city of Maastricht on suspicion of owning and concealing a deadly gas, a prosecutor's office spokeswoman Cindy Reijnders said in a telephone interview on Monday. She said police started monitoring a man's movements last week after a tip and arrested him on Friday as he was about to start digging in a field just outside Maastricht, a city close to the Dutch border with Belgium. Reijnders said police have no indication that any sarin was about to be used in a terror attack. "There are no legal activities you can use sarin for," she said. But at this moment we have no information or clues that it was going to be used for terrorism. Reijnders said police believe the four suspects may have been trying to sell the nerve agent for their own financial gain, although it remains unclear if they already had a buyer lined up. Sarin, first created by German scientists just before World War II, is a powerful nerve agent that was used in an attack by the Japanese doomsday cult Aum Shinrikyo on the Tokyo subway system in 1995 that killed 13 people and made about 6,000 others sick. One suspect was arrested on Friday as he was about to start digging in a field near Maastricht. Police dug up 400 square metres in the area to a depth of a metre without finding anything. Three of the suspects, whose ages range from 21 to 52 years, are Dutch citizens and one has Dutch-Turkish joint citizenship. Their names have not been released. They are due to appear before an investigating judge on Tuesday at a private sitting where prosecutors will ask for their continued detention while investigations continue, Reijnders said. According to the Organisation for the Prohibition of Chemical Weapons, sarin is a highly toxic and fast-acting organo-phosphorous compound that can be absorbed through the skin or by breathing it in. Exposure to a high dose of sarin can cause convulsions and loss of consciousness. Death can be caused by suffocation because of muscular paralysis and the effects the sarin has on the respiratory centre of the nervous system.