The West Hollywood boutique has been the sisters' flagship DASH store since it opened in 2012, relocating from Calabasas, California, where the reality TV star sisters first opened for business.
Since then they have opened two more shops in Miami Beach, Florida and New York City's fashionable SoHo district. Last year, the shops were the subject of a reality TV series which aired on America's E! Network.
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The arson attack is not the first time the sisters have been targeted by criminals; in 2014 Khloe's Los Angeles home was burgled, with thieves making off with US $250,000 (NZ $358,000) worth of jewellery belonging to her and estranged husband Lamar Odom.
The same year Kourtney was also a targeted by thieves, who stole US$50,000 in cash from her property in Calabasas. A further US $4,000 in cash was also taken from her home in The Hamptons, New York in a separate 2014 incident.
- WENN