Oscar Pistorius -- the Olympian now accused of murdering his model girlfriend -- was never violent toward her in the past -- this according to a source who worked closely with the victim in her modeling career.
The source tells TMZ ... she was with Reeva Steenkamp "a lot" during the months she was dating Pistorius and insists Steenkamp never mentioned or even insinuated there were issues of violence.
Our source says Steenkamp's family is in "absolute shock" because they never saw anything that would lead to harm.
The source -- who was frequently around Pistorius during the time he was dating Steenkamp -- says, she never saw a dark side -- to the contrary he was a "sweet guy."
The cops say there were previous domestic incidents at Pistorius' home, but they did not say the incidents involved Steenkamp.