Belgian police and security officials from the European Parliament are investigating the unauthorised use of Roscommon MEP's Luke Ming Flanagan's Twitter account.
The MEP says he's established that his account had been logged into on a third party app called Tweetcaster and this allowed an individual to tweet from his account using an old password.
He says the app was used twice on September 28th to access his account from Belgium.
Luke Ming says the police have been provided with the Belgian IP address associated with the use of the account, and are working to establish the exact location and identity of the person involved.