The influential KSU slammed the Congress-led government for making "a mockery of law" by releasing Jaintia Hills Autonomous District Council (JHADC) member Thomas Nongtdu within 48 hours of his arrest despite his alleged links with the slain criminal Fullmoon Dhar.
They are demanding that he should be re-arrested and "the involvement of politicians and businessmen in the Shillong jailbreak should be exposed".
Accusing the state government of lawlessness and blatant misuse of power in the wake of the jailbreak, KSU president Samuel Jyrwa expressed shock at the government's decision to drop all charges against Nongtdu even after revelations by the slain gangster's girlfriend Ibatiplang Kharkongor and Shillong Jail Warden Tobias Dkhar that the businessman-turned-politician had given money to Dhar.
Nongtdu was arrested last week on the charge of financing the purchase of arms for the jail-breakers.
Another influential organisation, the Civil Society Women's Organisation (CSWO) has demanded that lie detection and brain mapping tests should be conducted on Nongtdu and Ibatiplang to unearth the nexus behind the jailbreak.
Police, on the other hand, has claimed that the confession of Ibatiplang cannot be accepted as evidence against the JHADC member because she is "mentally ill".
CSWO president Agnes Kharshiing is demanding a CBI probe into the incident.
Dhar and six other under-trial prisoners had escaped from Shillong district jail on May 31 while they were being escorted for collecting firewoods. Dhar was killed in an encounter later on, while all the other escapees were caught in a police operation.