25/07/2014 03:21 BST | Updated 25/07/2014 03:59 BST

Peaches Geldof Defended By Sister Fifi After She Is Accused Of Being 'Selfish': 'You've No Idea What You're Talking About'

Peaches Geldof's sister Fifi has blasted a critic who branded the late star 'selfish and sad' for using drugs when she had children to look after.

The comment was made online after the inquest into Peaches' death concluded that she had died from overdosing on high-strength heroin.

Fifi Geldof

It was also revealed that the 25-year-old had hidden drugs in the loft of the family home she shared with her husband Thomas Cohen and sons, two-year-old Astala and one-year-old Phaedra.

Fifi, 31, reacted to the negative comments about her sister by posting a snap on her Instagram page, which read: “Don’t keep calm and f*** this. F*** that. F*** you. F*** off.”

She added a caption below it, saying: “Sums it up nicely about how I’m feeling about the viciousness today. Maybe now she’ll be allowed to RIP.”

A fellow site user then replied: “Think people are more annoyed at how she portrayed her life for her kids but was selfish to use drugs in front of them. Selfish and sad. Poor boys.”

But Fifi quickly hit back, saying: “You’ve no idea what you’re talking about quite frankly. Yet another who has bought into the bulls***.

Fifi, Tiger Lily, Pixie and Peaches pictured with Bob Geldof in 2005

Thomas Cohen has now revealed that Peaches was taking weekly drug tests, which she had told her husband were coming back negative.

However, although he never saw the star taking any drugs, he suspected she might have started using again.

Police investigating Peaches' death found "importation quality" heroin stashed in a cloth bag inside a cupboard in her bedroom.

The inquest revealed Peaches had 3mg of heroin per litre of blood in her system when she was found dead in April - ten times the level of her mum Paula Yates when she died of an overdose in 2000.

Photo gallery Peaches Geldof 1989 - 2014 See Gallery