The U.S. Department of State announced Friday a reward of up to $10 million for information leading to the identification or location of leaders of the Conti ransomware organized crime group. The agency also offered an additional $5 million on information leading to the arrest and/or conviction of individuals conspiring to participate in a crime with the group.

The department said the FBI estimates the group has over 1,000 victims over the last two years, with payouts exceeding $150 million, making Conti the costliest strain of ransomware ever documented.

An attack on the government computers of Costa Rica in April was noted in the press release announcing the reward.

On Sunday, Costa Rican President Rodrigo Chaves declared a national emergency following being sworn into office. According to BleepingComputer, Conti published nearly all of the 672 GB of data belonging to Costa Rican government agencies.

The ransomware gang allegedly demanded $10 million from Costa Rica's Ministry of Finance, which the government declined to pay.