"There's no amount of tears that will save you," said Anthonia Nneka Nwabueze. "Pistorius must face the law for brutally killing an innocent girl -- Reeva."
"My favorite athlete but what he did is grave and must be punished," Carlos Alvarez Ochoa said.
But another person who posted called for patience.
"(N)one of us were in the house when his girlfriend was murdered, let's hold off on casting stones at Oscar Pistorius," said Adrian van Liere Since. "Just like anyone else, he deserves a just trial, and in my eyes remains innocent until proven guilty."
Coming to his defense were two acquaintances.
"I've never seen him show an angry side. I've never seen him lose his temper," Vanessa Haywood, a model and longtime friend, told CNN. "He's an incredibly kind and gentle human being."
Another endorsement came from a former girlfriend.
"I would just like to say, I have dated Oscar on off for 5 YEARS," Jenna Edkins said on Twitter. "NOT ONCE has he EVER lifted a finger to me, made me fear for my life."
In an interview for Wednesday's "Anderson Cooper 360," Adam Steenkamp told Jake Tapper "there was no indication that anything was bad. I mean, we know Reeva. We knew Reeva. She was happy. And if Reeva was happy, everything was OK... and everything was good, then everything was normal."
Steenkamp said he never spoke to his half-sister about Pistorius, and she didn't discuss the relationship much -- if at all -- with anyone in the family. So, without any in-depth knowledge, his family keeps vacillating about what the evidence suggests happened, he said.
"At a time like this, when people are grieving, I think it's hard to keep a clear mind on anything," Steenkamp said. "And with the added pressure and the media coverage and the interest, you know, from the world looking into this story, it's a rather unnatural situation. So, I suppose I would agree with everyone is flipping from one side to the other. We just don't know. You know, all that we want is we want to know what the truth is, and I think that's what everyone else would like as well. You know, to be able to make something of this -- to be able to deal with this and have something positive come out of this."
Steenkamp said the worst is over.
"We are all holding up very well considering the circumstances. We've now had just about a week to let things sink in. And we've had a very busy few days as well," he said. "I feel like we have done the most difficult thing for us as a family, so far, in viewing my sister's body, and then attending her memorial yesterday. We're doing OK."