Rossouw (33) passed away on Monday in her Bryanston home. She was treated for gastric complications on Saturday and was later discharged from hospital.
A friend found her body in her flat after she failed to arrive for a dinner date. The cause of her death was unknown.
Rossouw's body was due to be flown to Cape Town for funeral arrangements.
The former Mail & Guardian deputy politics editor and reporter was described by M&G editor-in-chief Nic Dawes as "an extraordinary presence in our newsroom and in our pages; vivid, acute, and determined to break the story".
Rossouw broke some of the biggest news stories while she was deputy politics editor for the M&G. She was the first to reveal the story of President Jacob Zuma's Nkandla mansion in rural KwaZulu-Natal. She had insight and a clear understanding of the news, which was demonstrated in the numerous articles she left behind.
She left the M&G and joined City Press and Eyewitness News as a politics reporter, and joined Media24 as an international correspondent.
Three of Rossouw's colleagues at the M&G wrote tributes to her.
M&G politics editor and deputy editor-in-chief Rapule Tabane:
When we first recruited Mandy to the M&G in 2007, she had been working in the Afrikaans press for a while and wanted a break in the mainstream English media. I knew her from Parliament when we used to go down for the weekly ministerial briefings that government organised after every State Of The Nation. She had a razor-sharp mind and invariably had a question for most ministers.
When we had an opening for a politics reporter post, I decided we should take a chance on her. It was a risk because although I always saw her in action, I had never actually read her stories because they were in Afrikaans. But little did we know that we had landed such a gem. She was indefatigable and prolific and would produce five stories for the paper in a week without blinking an eyelid.
She was also strong willed and continued to do well even after she left us in 2011. She loved her work and enjoyed all the publicity, the controversy, and the travelling that came with it. She always wore a smile to work (with those dimples) and loved the thrill of chasing a story. Along with Matuma Letsoalo and Mmanaledi Mataboge, we had the strongest team of politics reporters. She will be sorely missed by all of us.
M&G politics reporter Matuma Letsoalo:
It is really hard to come to terms with the fact that Mandy Rossouw is no more. The last time I saw her was during the ANC's January 8 statement in Durban and she looked happy and energetic as usual. Her sudden death is a great loss, not only to our industry, but to society at large.
Although she left the M&G to join City Press two years ago, she remained a close friend and a reliable colleague, who would not hesitate to share information for stories. While she was younger than me, I learnt a lot from her and enjoyed covering politics stories with her.
She had an amazing energy and never ran out of ideas. When the rest of us struggled to present story suggestions during our regular diary meetings on Mondays, Mandy would have five stories to work on for the week. But what I found most remarkable about her was her ability to burst into laughter regularly, even when she was under deadline pressure.
M&G politics reporter Mmanaledi Mataboge:
Mandy went the extra mile for every colleague if it meant getting a story. One day she waited up in a hotel bar until around 2am, drove me to a meeting with a source and was willing to wait because that guaranteed a unique breaking story. "Take your time," she said as we parted ways at a hotel reception in a city that we both did not know – the city whose streets she was willing to navigate at midnight to make sure I got the story we needed for our newspaper. She would not complain about the waiting or the workload. She was always there to help colleagues. When my brain blocked in the middle of writing a story I'd call her, regardless of what time it was, and she'd take the call and offer advice.
I still have a chair she left at my house in August of 2009. For years she refused to take the chair because I just moved into the house when she visited and did not have chairs for my dining room. To this day, that chair is a reminder of the selfless person she was. She would never go on an overseas trip and come back empty-handed. She brought back chocolates and souvenirs for almost every colleague.
After a lot of persuasion I got her to eat Chicken Licken for the first time in 2010 during the ANC's national general council in Durban. I had to restrain her excitement in the middle of the packed restaurant. She could not stop talking about how affordable and tasty the hotwings meal was. All eyes were on us, but she did not notice because she was just too excited to worry about who was looking. That was how much of a free soul she was.
City Press editor Ferial Haffajee and assistant editor Adriaan Basson also released a statement on her death.