Kardashian was pelted with flour at a charity event in Hollywood last week (22Mar12) over her reluctance to give up fur and earlier this week (beg26Mar12), her sister Khloe quit as a People for the Ethical Treatment of Animals (PETA) anti-fur spokeswoman over the attack.
But activist Krupa insists Kim deserved worse than flour bombing and suggests Khloe stepped down because she's too embarrassed to fight fur wearers when her sister is one.
The outspoken model tells HollyScoop.com she has proof that the Kardashians are selling fur at their Calabasas, California store Dash.
She says, "They told PETA multiply times they don't sell fur at Dash... and we caught them cold-handedly at their Calabasas store."
Krupa claims a fellow activist purchased a rabbit fur vest for $297.98 (£186) at the store - and she has the receipt to prove it.
She is now planning a protest in early April (12), and wants to present the Kardashians with a 140,000-strong petition in an attempt to force the sisters to stop selling fur at their boutique.
And she adds, "I believe the reason Khloe quit working with PETA is because she was getting so much heat, being a hypocrite - posing for the anti-fur campaign, and then selling fur in her Dash stores."
Asked about the flour-bombing attack on sister Kim, Krupa adds, "She got away easy with just flour. The attacker is a hero."