The Manipur police on Thursday arrested one of the main accused who was seen in a May 4 video of two tribal women being paraded naked and molested by a mob at a village in Senapati district, officials said.
They said several police teams were formed immediately after the video of the incident surfaced.
One of the people, alleged to be the mastermind, was arrested from Thoubal district, officials said.
The accused was prominently seen in the 26-second clip.
The police had issued a statement on Wednesday saying a case of abduction, gang rape and murder has been registered at the Nongpok Sekmai police station in Thoubal district against unknown armed miscreants and that all-out efforts were on to arrest the culprits at the earliest.
Manipur has been witnessing ethnic clashes since May 3 between the majority Meitei community, concentrated in the Imphal valley, and the tribal Kukis, occupying the hills. Over 160 people have been killed in the violence so far.