Hlanjwa, a third-year maritime student at the Cape Peninsula University of Technology (CPUT) was last seen on August 1.
She left a chilling note reading “Start your search in Camps Bay if I am missing for more than 21 days” in her room at the Catsville Residence.
Her older sister, Lazola, said that when she called her on the morning of her disappearance, she couldn’t reach her and thought she was in class.
“At night I tried to call her again but it went straight to voicemail and even then I assumed she was studying because I knew she had some tests or project; when she studies she switches off her phone.
"The next day she didn’t call me back. I called again but her phone went straight to voicemail.That’s when I got worried and called the residence mother (someone in charge of the residence) to check if she was fine,” said Lazola.
She said the person in charge had gone to her room and found the note. “She informed me of the disturbing note and we spoke to her friends who said they had also been worried as they couldn’t get hold of her and she had missed classes, something she never does.
“At that point I was terrified and went to the residence to try to find more leads. Some students said they saw her carrying a fleece and backpack. It’s like she knew she might be going to an unsafe place,” said Lazola.
She said her sister always put her studies first and was an open person who always told people where she was.
Police spokesperson Andrè Traut said Hlanjwa had been reported missing at Woodstock police station.
Meanwhile, police have asked the public to help find 13-year-old Carin Coert, who was last seen in Annadale Road, Stellenbosch on Monday. At the time she was wearing grey trousers, white shirt, pullover and jacket.
The search for Leah Jovic Hall, 15, from Hout Bay, continues. She was last seen by her family on Tuesday. She was wearing a grey tracksuit top, grey trousers and green takkies with a gold stripe. She looks older than she is because she is tall.
Anyone with information can anonymously contact Crime Stop on 08600 10111 or SMS Crime Line on 32211.