Nottinghamshire Police said officers were investigating whether any criminal offences had taken place at the care home.
A spokeswoman said: "A police investigation has been launched after concerns were raised about the standard of care provided to residents at Autumn Grange in Sherwood Rise."
Police will be speaking to former residents and their families and will work closely with partner agencies to establish if any criminal offences have taken place."
More top news
Alex Salmond found himself in a stand-off with airline staff after booking on to a flight under the name James Kirk.
Romelu Lukaku equalised to ensure Everton earned a point after Danny Ings had given Liverpool the lead in a heated derby clash.
Postman suspended as part of probe as hundreds of letters from a Black Country delivery office took two and a half years to arrive.