In the late 1940s, as tensions over a soon-to-be divided Korean Peninsula simmered, a protest on Jeju Island was ruthlessly suppressed, claiming as many as 30,000 lives.

Now a group of scholars and clergy from the island are endeavoring to raise awareness of the U.S. government and military’s role in the incident.

From March 24-29, the group visited Washington, D.C. to submit the Jeju 4.3 Incident Investigation Report. The “4.3 Incident” refers to a particularly bloody incident in 1948 between Jeju residents and authorities. On March 1, 1947, police fired on demonstrators commemorating the 28th year after the March 1st independence movement opposing Japanese colonization.

A full-scale uprising took place the following April 3, when police again fired on protestors, causing outraged demonstrators to attack multiple police stations, resulting in scores of deaths among police and civilians.

In November 1948, Syngman Rhee, South Korea’s first president, declared martial law on Jeju. Reports vary, but over the 13 months anywhere from 14,000 to 30,000 were killed. Though May 1949 is generally considered the end of the Jeju Uprising, resistance and oppression continuned: After the North Korean invasion in 1950, numerous suspected leftists were rounded up by authorities, and many executed.

The report was published by the National Committee for the Investigation of the Truth about the Jeju April 3 Incident on March 29, 2003, after a six-month review and revision for objectivity and fairness.

The massacre happened during the U.S. military’s government of the southern part of Korean Peninsula after the end of Japanese colonization. People who opposed the division of the country protested against the formation of two governments, and Jeju residents actively participated in the protest.

According to the report, the U.S. intervened in the Suppression Operation, killing numerous residents.

“The U.S. Military Government and the Provisional Military Advisory Group (PNAG) are not free of responsibility for the occurrence and suppression of the incident. The U.S. Army Colonel in Jeju directly commanded the Suppression Operation. The U.S. Army supplied weapons and observation aircraft for the Suppression Operation,” the report said.

“We visited the Senate, House and Congressional Library to convey the report. The report was published in 2003, and endorsed by the South Korean government. In 2013, our group from Jeju University translated this into English,” the group’s leader Ko Chang-hoon, professor at Jeju University, told NK News.

Ko said the incident and the U.S. militaryʻs responsibility for the massacre has not been well-communicated to U.S. citizens.

“It was the main purpose of our visit, sharing the responsibility with the U.S. people, in order to heal the wounds … Also, we aimed at cooperating with U.S. scholars currently studying this incident,” Ko said.

To further publicize the studies, an event took place in late March in Washington, D.C., covering the issues of social justice, authentic reconciliation and international compensation. The speakers included U.S., Japanese and South Korean scholars and activists.

Though there isn’t any evidence the Jeju protest was organized by the Workers’ Party of South Korea (Namrodang), the people of Jeju had long been under surveillance, and their social activities were controlled. The perception of an “island of reds” was created by U.S. and South Korean military officials and national police, which contributed to the sustained violence.

And long after the uprising, the anti-communist South Korean government suppressed even mentions of what happened on Jeju.

“It was impossible to mention the massacre until the early 2000s before President Kim Dae-jung. Until then people from Jeju were labeled ‘commies,’ meaning North Korea followers,” Yang Young-soo, one of the Catholic priest visiting U.S. told NK News.

Scholars define this incident as a spontaneous movement to prevent division, rather than organized protest directed by North Korea.

“Basically, it was anti-division movement. … it was spontaneous protest,” Shin Yong-ok, who lectures on modern Korean history at Korea University, told NK News.

In the aftermath of this event, many households on Jeju Island have a memorial service for their ancestors on April 3.

“During the massacre, 10 percent of Jeju’s residents were killed. The survivors were faced with collective punishment and suspicion thereafter, blocking their careers as public servants, including as policemen or soldiers. Some of the victims of torture and imprisonment are still alive,” Kim Jae-hyun of the Jeju April 3 Peace Foundation told NK News.

Ko and other civil and religious activists are preparing to petition U.S. Congress, aiming at organizing the “Joint South Korea and United States Jeju 4.3 Incident Task Force on Social Healing through Justice.” Peace Island Asia started the petition in March 2014, and is planning to gather more than hundred thousand of signatures by April 2016.

“The petition is completely based on proven documents, the report published by the national committee,” Ko said. “It would help create a new comprehensive history that gives voice to the people. It would embrace concerns about dignity and autonomy.”

Featured image: Ko Chang-hoon