1998 East Java ninja scare

In early 1998, residents of Kaligondo village in Banyuwangi Regency, East Java, grew concerned about sorcery after several cattle sickened and died. A local resident, Soemarno Adi, was suspected of practicing black magic and was lynched on 4 February 1998. His death set off a wider series of killings carried out by vigilante groups targeting people suspected of being sorcerers, including ordinary civilians, local leaders, and clerics affiliated with Nahdlatul Ulama. Some of the attackers wore all-black clothing, leading them to be described locally as "ninjas."

In response to the killings attributed to these ninja-like vigilantes, other community members began attacking and killing people they suspected of being ninjas themselves — often individuals who were out after dark or unable to produce identity documents. The phenomenon spread beyond Banyuwangi into other parts of East Java and later into Central and West Java, although no ninja-attributed killings were confirmed to have occurred in those latter regions. By November 1998, police in Central Java had detained roughly 200 mentally ill individuals as a protective measure, since they were considered at elevated risk of being mistaken for ninjas if found outdoors at night.

Specific violent incidents included the killing of five men in the Turen area on 18 October 1998 — one beaten to death, one burned, and three beheaded — and three killings on 20 October 1998, in which two men were reportedly seized from a police vehicle by vigilantes who slit their throats, while a third was beheaded and his head displayed on a stake. On 24 October, five more suspected ninjas were killed by villagers in Gondanglegi, Malang Regency, with one victim burned to death. Between 31 October and 1 November, three policemen were killed in Madura after being suspected of being ninjas, and on 31 October a man in north Jakarta was attacked on similar suspicion, marking the scare's first documented impact on Jakarta.

Local newspapers, including the Surabaya Post and Jawa Post, reported in October 1998 on rumors of black-clad death squads targeting community and religious leaders, prompting neighbors to organize guard shifts around the homes of ulama.

The violence largely subsided by the end of 1998, though a further, similar spate of killings occurred in December 1999. The National Commission on Human Rights concluded in 2018 that the killings were carried out by "trained" and "organized" assailants, and that national security forces failed to intervene until September 1998, effectively enabling the violence. Some observers and organizations, including Nahdlatul Ulama, have alleged military involvement intended to destabilize the post-Suharto government or weaken Nahdlatul Ulama and an emerging Islamic political party. Anthropologist Nicholas Herriman has characterized the events primarily as local residents killing other local residents believed to be sorcerers, linked to perceptions that the government could not adequately protect communities from sorcery-related threats. According to the National Commission on Human Rights, 307 people were killed in total: 194 in Banyuwangi, 108 in Jember, and seven in Malang.