Earlier this month, the force said that a man grabbed a woman in the Springfield area in the early hours of 9 September before she managed to break free and run away.
Now they have revealed that another woman was followed in the early hours of 23 September.
They have also released CCTV footage of a man they want to speak to in connection with the first incident.
In a statement, the force said: ‘The footage shows a man dressed in black (some of the footage appears to show a light-coloured top, but this is merely due to the way light is absorbed when using an infra-red camera) walking along various streets and although there is not a clear image of his face it could be familiar to someone who knows this man.
‘We would like to speak to the driver of the taxi that passes the man in Rouge Bouillon and also the witnesses seen on the CCTV to be standing on the other side of the road in Cheapside as the man walks up toward St John’s Road.’
In the second incident, a woman in her 30s who had been enjoying a night out in town was walking home at approximately 2 am to 2.30 am when she was followed home by a man.
She left a bar in Mulcaster Street and walked through the Royal Square towards Bath Street, then from Bath Street into Belmont Road, along Simon Place before turning left into St Saviour’s Road.
As she approached the Monterey Hotel in St Saviour’s Road at about 2.30 am to 2.45 am, the man asked her if she was ok. There was a couple walking nearby who turned into Stopford Road and headed down the road in the direction of David Place.
After turning into her driveway and walking to her door, the man continues to follow the woman, at which point she challenges him before going inside.
The man then walked off. He is described as being between 25 and 35 years old, about 5 ft 8 ins tall and unshaven. He had dark hair, dark eyes and a tanned appearance, possibly Mediterranean and he spoke in broken English. He was wearing a knee-length navy mac, zipped up to the neck.