An elderly woman has recalled how she cried out for help after being sexually assaulted in her apartment block.
The grandmother, in her 80s, was attacked by a man in his early 20s after exposing himself to her in a lift in Melbourne's inner south.
The man is believed to have waited for the woman to enter a lift in South Yarra in a targeted attack at 2pm on April 1.
He followed the woman to another floor of the Simmon Street housing commission block and sexually assaulted her.
The woman said she attempted to end the man's attack by using her walker to push him off.
She screamed out for neighbours' assistance as he ran away.
"I cried, 'help, someone help' and a lady opened the door and heard me terrified," she said.
The woman said she no longer felt safe in her home and was scared the man would return to strike again.
"I sometimes (now) feel stressed when I open the door because there's no one else here," she said.
"He is bad, very, very bad."
The attacker is not believed to be a resident of the building or local to the immediate area surrounding it.
Detective Senior Constable Andrew Turton from Bayside's Sexual Offences and Child Abuse Investigation team said there have been no known sightings of the man since the attack.
"Concerningly, it appears he has waited for a period of time in the foyer, he was there for about 45 minutes before selecting our victim," Det Turton said.
"This is an additional concern to us as it doesn't seem to be an opportunistic thing, it seems to be a targeted attack."
The man is believed to have evaded the building's security by following another resident through its doors before the assault.
Victoria Police believe the man is about 180cm tall, with shaved black hair and is perceived to be of Asian descent.
He was last seen wearing a black hooded jumper with the word 'Jordan' written on the back along with black pants and black sneakers.