Which method involves keeping items in separate locations to mask their true ownership in fraud cases?

The method of commingling of goods involves mixing different items or assets together, which can obscure their individual ownership and make it difficult to trace their origins. In fraud cases, this can be particularly deceptive, as it can create the illusion that the goods belong to different parties, thereby masking the true ownership. This strategy is often employed to hide illegal activities or the provenance of items, making it a common tactic in fraudulent schemes.

In contrast, the other methods listed serve different purposes. Double invoicing refers to the practice of submitting two invoices for the same goods or services, which can lead to overcharging. Separate payments typically involve distributing payments for the same transaction across various accounts to evade detection, but it doesn't necessarily involve obscuring ownership directly. The term undeclared usually pertains to items or income not reported to authorities, rather than directly relating to the separation of ownership. Each of these other options addresses different aspects of fraud but does not capture the essence of obscuring true ownership through physical separation of items as effectively as commingling does.