Banksy could be unmasked after police launched an investigation into potential "criminal damage" following an incident at the Royal Courts of Justice.
A new Banksy mural depicting a judge beating a protester, was spray-painted on the Grade I-listed building on Monday. Despite being promptly covered up by officials, Banksy shared an image of the artwork on Instagram.
Security guards have since been seen patrolling the scene as the artwork was concealed.
The Metropolitan Police said it had launched a probe into the graffiti following a report of "criminal damage".
Scotland Yard also confirmed that enquiries were continuing into the incident.
However, speculation that the police could uncover Banksy comes after the popular street artist has remained anonymous for nearly three decades. If he were to appear in court, his name would have to be disclosed.
HM Courts and Tribunals (HMCTS) has said the artwork was going to be removed from the building. "The Royal Courts of Justice is a listed building and the HMCTS are obliged to maintain its original character," a spokesman said.
While there is no direct explanation of the artwork, it appears to reference protesters being arrested.
It comes after nearly 900 people were arrested in central London at Saturday's demonstration in support of banned group Palestine Action - it is believed to be Britain's largest ever mass arrest.