A statement posted on the social media site read: "A murder investigation has been launched after a man was stabbed to death in a city centre bank.
"The man, who was a customer, was assaulted inside the Lloyds bank in St Peter’s Street at around 2.35pm today (6 May).
"The man, aged in his 30s, was pronounced dead at the scene. While formal identification has not taken place, his family have been made aware.
"A significant police presence remains in the city centre and will do for some time to come.
"Anyone with any information that can assist is asked to contact the force using the 999-emergency number with reference 678 of today."
