Levy, 41, was sentenced to a whole-life term last week for killing grandmother Carmenza Valencia-Trujillo, 53, in March last year and mother-of-four Sheryl Wilkins, 39, five months later in August 2025.
He was also sentenced for the rape of a third victim, who was left for dead near his home in Tottenham, north London, in January last year.
Levy attacked all three women, who were vulnerable sex workers, while he was on bail for carrying out a string of sexual assaults on busy London Underground and Overground trains.
He was first arrested by BTP on 4 November 2024 over an attack carried out the month before, but was bailed by police, who did not carry out an identity parade until February the following year.
Levy had struck twice more on public transport in October 2024 and by the time of the identity parade he had raped a woman, who cannot be identified because she is the victim of a sexual assault.
BTP said the force had made a voluntary referral to the Independent Office for Police Conduct (IOPC) watchdog, which confirmed it would conduct an investigation.
“The IOPC investigation relates to two BTP officers and the investigation conducted into two sexual assaults carried out by Levy on the London Underground in October 2024,” a BTP statement said.
“It’s in the public interest for independent and objective scrutiny to be applied, and we will fully co-operate with the IOPC’s independent investigation.”
The force previously said the initial investigating officer had since returned to uniformed duties, while the supervising Detective Sergeant received advice and guidance and carries out a non-investigative role.
The BTP, Metropolitan Police and Crown Prosecution Service (CPS) have all faced serious questions over how convicted sex offender Levy was allowed to sexually assault, rape and murder women between February 2023 and August 2025.
The CPS has apologised for its failings, while the Met has also referred itself to the police watchdog, with two of its officers under investigation.
The IOPC previously said it was investigating the management of Levy from his first conviction in 2021 up to his arrest in September 2025.
