SEOUL — Investigators in South Korea are looking into North Korea’s possible involvement in a heist from a bitcoin BTCUSD, +4.54% exchange that collapsed here on Tuesday, according to people familiar with the situation, as the regime develops new ways to raise money as sanctions choke off its traditional revenue sources.

The investigation into the hack, led by South Korean law enforcement and a state cybersecurity agency, is still in its infancy and a review of the malware code could take weeks, the people said. But the people said there were telltale signs and historical evidence that North Korea, which has turned in recent years to increasingly sophisticated financial warfare, was behind the hack of Seoul-based exchange Youbit.