An arrested ambulance driver of the private home at Gurap in Hooghly where the dumb woman had died on July 1, led a CID team during the day to the bank of the Damodar river at Jamalpur near Charabagan Tulmatha village in Burdwan where the bones were dug up, police said.
A member of the CID team, Sarbari Bhattacharya, said the area was searched and the bones found after information provided by driver Somnath Roy.
Roy earlier told the CID that he had come with three others from the home with the body of a woman inmate Jharna Samanta on May 6 to bury it at Jamalpur.
Roy had told the police that villagers of Charabagan Tulmatha, however, had disallowed the three to bury the body and handed it over to the police.
"But the police did not investigate properly and instead handed it back to the home authorities," SP S M H Mirza said.
The officer-in-charge of Jamalpur police station Rajat Kanta Pal and ASI Biswarup Prasad Dikshit were relieved from duty and posted at the Burdwan police lines for dereliction of duty last night in this connection, he said.
The three others named by the ambulance driver Shyamal Ghosh, Tarumal Das and Uday Chand Kumar were yet to be arrested, the police said.