"I request you to fix the responsibility for the illegal killing of the tigress and consider removing Mugantiwar from the responsibility of the Ministry of Environment and Forest in the state government. I have personally known you an animal welfare person and I am sure you will consider my request," Maneka wrote in the letter.
The minister also stated that she had been in talks with Mugantiwar for the past two months and had repeatedly requested him to ensure that the tigeress was tranquilized and quarantined.
"But for some inexplicable reasons, Mugantiwar has been repeatedly calling Shafat Ali Khan to kill the animals in Maharashtra. As ministers, we need to exhibit the highest standard of sensitivity to the constituencies that we serve," she added.
Avni was a five-year-old tigress identified as T1 who had caused widespread fear in Maharashtra's Vidarbha forests. She was shot dead early on Saturday near Borati village in Yavatmal district.
Maneka earlier had hit out at the minister on Sunday saying that it is a "straight case of crime" and said that Mugantiwar had earlier directed killing a dozen of leopards and 300 wild boars.
"I am shocked that such a person is continuing to hold a ministerial position. Every time he has used the Hyderabad shooter, Shafat Ali Khan, and this time his son has also appeared on the scene to kill the tigress. His son was not authorized to kill. This is patently illegal," she added.
Avni died after three months of a massive hunt undertaken with the help of trap cameras, drones, trained sniffer dogs along with a team of forest department officials and spotters.
As per Supreme Court directives, forest department officials are required to first tranquilize and trap such an animal, but in Saturday's operation, Avni allegedly attacked the stalking team which shot her.