Four women were killed and threepeople sustained injuries when soil caved in near Adasa Patkakhedi village in Nagpur district on Friday morning, police said.Anusaya Hirdey Tekam (45), Varsha Shamlal Madavi (26), Sunita Kailas (35) and Rampyari Udaysingh Kakoria (18), all residents of Seoni district of Madhya Pradesh, were engaged in digging work along with 30 others to build a small dam when the incident happened, an official said."We have registered a case of causing death by negligence against contractor Mandeep Choudhary and engineer Jagdish Prasad," said Inspector Ashok Koli of Saoner police station.