Police from Melbourne West are investigating a series of mail thefts in Melbourne's CBD.
On the first occasion, investigators believe a man followed residents into the Collins Street building about 1.30am on 29 December.
Once inside the building he made his way to the ground floor mail room where he removed a number of items from mail boxes.
He is perceived as Caucasian in appearance and about 25-30 years old with an average build.
At the time he was wearing a grey hoodie with a black baseball cap with the logo GLTH90, grey pants and dark-coloured runners.
He was also carrying a black satchel bag over his shoulder.
On 7 January police believe a man and woman followed residents into the same building about 11.30pm.
They both entered the ground floor mail room where they stole a large amount of mail.
The woman is about 20-25 years old with long black hair and has a thin build.
She was wearing green pants and dark blue runners, and was carrying a black canvas back with a 'Cotton On' logo on the front.
The man is perceived as Indian or Middle Eastern in appearance and aged between 20-25 years old with a dark beard and moustache.
He was wearing grey pants, a black jacket with white writing on the back, and a black cap.
Investigators have released CCTV and images of two men and a woman who they believe may be able to assist with their enquiries.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
