THE HAGUE, Netherlands (AP) — Dutch police spent three days digging up a field after receiving a tip that sarin may have been buried there, but they found no trace of the deadly nerve agent, a prosecutor’s office spokeswoman said Monday.

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, spokeswoman Cindy Reijnders said in a telephone interview.