A mystery that started during week two of The Block ended in two arrests last night.

When The Block’s Scott Cam discovered some odd purchases on the credit card issued to contestants Jess and Norm, he accused them of reckless spending.

In an episode during week two of the Channel Nine renovation show last month, the pair were admonished for going over budget – but also for spending money on things outside their renovation needs, including alcohol and fast food.

“I understand what you’re saying but I can promise you with every soul that we have not [used the credit card for that.]” Jess insisted at the time. “We would never do that in a million years.”

Concluding that the card must have been stolen, the pair were told it would be "investigated".

And in last night's episode, the couple learned exactly who had been using their credit card.

Jess and Norm were left stunned as two tradies who had been working on their Gatwick hotel renovations were hauled away by police.

"I sung Happy Birthday to them! I’ve given them food and drinks!" Jess exclaimed.

"They stole our credit card from inside our apartment and still smiled at us for the last few weeks. I cannot believe it."

Among the outlandish purchases on the card were trips to a fishing and tackle shop, a bar, a camping store and almost $100 at a roast chicken shop.

“For them to look at you in the eye every single day and be like ‘Hello!’, and they’ve bloody stolen off ya. That’s insane," Jess said, adding the pair looked "sad" in their handcuffs.

Viewers learned the pair were taken to South Melbourne police station. One was convicted of theft and credit card fraud, resulting in his deportation, while the other was released.

A still shocked Jess and Norm were refunded of all the money spent by the labourers.

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