However, no arrest has taken place in the matter.
"Action was taken against the four for negligence of duty," said P Ringu, Deputy Conservator of Forest (Wildlife).
After post-mortem, the six-year-old tigress' body was cosigned to flames during the day within the zoo campus in presence of a magistrate and the police, Ringu said.
Miscreants shot Oni, the six-year-old tigress, to death in her enclosure on Monday night, and left with her flesh without taking the valuable skin, teeth, and claws, leaving the authorities puzzled about their motive.
The zoo in-charge Zoram Dopum had said yesterday that the miscreants could not take the valuable body parts probably because the guards had returned by then after dinner.
Ringu said the police have launched an investigation but so far no arrests have been made.
Sleuths of the Wildlife Crime Control Bureau (WCCB) were expected soon to start a probe, he said.
During postmortem, the doctors found two wounds in the tigress' head apparently caused by bullets from a .22 rifle, Ringu said adding the microchip implanted in her body in September 2007 was also found.
He said, the microchip implanted to study Oni's behaviour had been sealed and kept carefully as it could help the WCCB investigators.
