Leicestershire Police investigated over acid attack information
A police force is being investigated over claims it knew acid had been bought for use in a planned attack.
Leicestershire Police is also said to have known Mark Cummings and Katie Leong were meeting in breach of a restraining order.
On Tuesday, Leong was sentenced to a minimum of 17 years in prison after being found guilty of attempted murder.
The force said it is co-operating with the Independent Police Complaints Commission (IPCC).
In July last year Daniel Rotariu was attacked with 96% pure sulphuric acid while he slept in his bed in a property on Turner Road, Leicester.
The attack left him blind and with burns to 32% of his body, for which he still requires treatment.
Leicester Crown Court heard Leong had become fixated with carrying out an acid attack.
In his evidence, Mr Cummings told the court he had raised concerns about why Leong wanted to buy the acid to his probation officer.
A spokesman for the IPCC said a referral from Leicestershire Police was received in August last year, and an investigation can now proceed following the conclusion of the trial.
IPCC commissioner Derrick Campbell said the investigation would examine "whether the police response to the information received was appropriate".
A spokesman for Leicestershire Police confirmed the referral was made after the attack "into what the force may or may not have known and how we responded to information about the two defendants".