A briefcase filled with £2,385 of cash was taken from their bedroom in early July, Scott reported to the Southampton Town Police, according to TMZ.
The American website went on to add that Kourtney suspected that the crime was an inside job, perhaps carried out by someone on the filming crew of Keeping Up With The Kardashiansas they have access to the reality TV stars' home.
According to police, there was no sign of forced entry and nothing else was reported stolen.
The long-term couple are currently residing in the New York summer getaway to film Kourtney & Khloé Take The Hamptons along with other members of the Kardashian crew.
This is not the first time that Scott and Kourtney, who is pregnant with the pair's third child, have been hit by theft.
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Last February, almost £300,000 was stolen from a briefcase in their home in Calabasas, Los Angeles – the city where Kourtney, her younger sisters Kim and Khloé and brother Rob were born and raised.
Kourtney is said to have left the money in a safe place for a few days, but when it came to deposit the cash, it was gone.
Around the same time, Khloé was reported as a victim of a £150,000 jewelry robbery. The fashion designer and businesswoman had watches and gold chains pilfered from her and her estranged husband Lamar Odom's home in Tarzana.
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The house had been sitting empty for a month after the couple went their separate ways, and Khloé only discovered the theft when she returned to clean out the house for new owners Kaley Cuoco and Ryan Sweeting.
Police reportedly believed that both cases were an inside job as there were no signs of forced entry reports Hello News.
We hope they get their property back and quickly they do not need to be robbed this close to a new baby on the way.