"I woke up in a happy, safe home this morning," she tweeted. "Not everyone did."
Four days after she posted that message, neither did she.
The 29-year-old model was shot dead by her boyfriend at his house in Pretoria. She died on Valentine's Day in 2013.
Pistorius has admitted to shooting Steenkamp but says he mistook her for an intruder.
Beauty and brains
Before she started dating Pistorius, Steenkamp was famous in her own right.
She was a striking, platinum-haired model, gearing up for her reality television debut.
A law school graduate, she had a vibrant personality and a slew of modeling gigs under her belt.
Her growing exposure brought more opportunities. She was a presenter for FashionTV in South Africa, an FHM cover girl and the face of cosmetics company Avon.
FHM described her as a "beautiful, intelligent and warm-hearted woman" who had a "wicked" sense of humor.
"She was the kindest, sweetest human being, an angel on earth," said Capacity Relations, the agency that represented her.
And her fame was growing.
'I don't have any regrets'
Two days after her death, a pre-recorded reality show in which she appeared as a contestant aired. In the context of what transpired, her message in it sounds haunting.
"I'm going home with sort of a sweet taste in my mouth. I don't have any regrets. I don't have any bitterness," she said as she blew a kiss to the camera. "I'm going to miss you all so much and I love you very, very much."
South Africa's national broadcaster aired the show "Tropika Island of Treasure" showing a clip discussing her exit from the taped program. The show features local celebrities competing for prize money.
Steenkamp was born in Cape Town but moved to Johannesburg years ago to pursue modeling.
The two became an item around November 2012, and were popular in South African social circles.
She constantly referred to him as "my boo" on social media and posted pictures of their vacations together. But phone messages read during the trial showed a couple that had some rocky patches as well.
In some of the messages, she accused him of being overly jealous and overbearing. But he said he loved her and was planning a life with her.
About a month before her death, the model shared a picture collage that included the runner.
"Some of my favorite people," she described the picture.
Shortly after they met, she posted a message that appeared to make a reference to their love.
"The only guy you need in your life is the one who proves that he needs you in his," she said.
They had big dreams
Pistorius' relatives said she made him happy.
"All of us saw at first hand how close she had become to Oscar during that time and how happy they were," said Arnold Pistorius, his uncle.
Both had big dreams, the uncle said.
"They had plans together and Oscar was happier in his private life than he had been for a long time," he said. "We are all grieving for Reeva, her family and her friends. Oscar -- as you can imagine -- is also numb with shock as well as grief."
The younger Pistorius made history when he became the first Paralympian to compete in the able-bodied Olympics in London in 2012. He ran on special carbon fiber blades affixed to his legs. He was born without the fibulae in his legs, and they were amputated below the knee when he was 11 months old.
Before she died, Steenkamp sent out a message urging her thousands of social media followers to empower women.
"Speak out against the rape of individuals" in South Africa, she said in a post on the photo-sharing site Instagram. "RIP Anene Booysen."
Booysen, 17, was raped and mutilated in South Africa in February 2013, putting a spotlight on violence against women in the nation.
Steenkamp urged her followers on Twitter to wear black the day after Valentine's to protest violence against women.
A tragic end on Valentine's
Steenkamp was looking forward to Valentine's Day.
"What do you have up your sleeve for your love tomorrow?" she asked her Twitter followers the day before. "Get excited."
At dawn, she lay dead in a pool of blood.