The PSNI have said that they believe that their Chief Constable George Hamilton's Twitter account may have been "maliciously hacked".
The incident happened earlier Thursday, with a number of other Twitter users querying why a tweet had been removed from his account.
It is unclear what it referred to, but responding tweets have indicated that it included a number.
In a statement, the Head of the PSNI's Cyber Crime Centre Detective Chief Inspector Michael Harvey said: "At this time we believe there is a possibility the account was maliciously hacked. Enquiries are currently ongoing. There are no further details at this time."