Ms Bailey, who formed Cure the NHS and fought for public inquiries into abuse at Stafford Hospital, was reportedly the target of abuse and vandalism to her mother's grave in Stafford.
This year it appeared the backlash had got too much for the former cafe owner who left her hometown and moved to an undisclosed location.
Staffordshire Police spokeswoman Faye Casey said: "Detectives were made aware of a number of issues, including damage to flowers and vases at her mother's grave," she said. "Clearly, such offences are completely unacceptable."
She said police began an investigation which involved taking witness statements, carrying out inquiries and examining CCTV footage.
"We've now finished our detailed inquiries and, at this stage, we have not been able to recover evidence which could help us identify offenders.
"After being made aware of the issues we put in place a number of measures to protect her safety. We will continue to maintain contact with Ms Bailey."
Ms Bailey's mother Bella died in Stafford Hospital in 2007. Her campaigning led to two public inquiries conducted by Robert Francis.
The first inquiry saw Mr Francis make 18 recommendations for both Mid Staffordshire NHS Foundation Trust and the Government based on evidence from more than 900 patients and families who contacted the inquiry with their views. The second made 290 recommendations to the Government in the wake of the Mid Staffs scandal.
Under proposals, the Mid Staffordshire NHS Foundation Trust is to be dissolved with the running of Stafford and Cannock Hospitals being taken over by University Hospital North Staffordshire and the Royal Wolverhampton Hospital Trust.