The body of the lioness, which was pregnant, was recovered from Hiren river on September 1. The PIL alleged that the investigation conducted by the forest department into the death made no headway.
According to the petitioner Biren Pandya, the autopsy report showed that the lioness died after receiving an electric shock. Also, two lions accompanying her were still missing.
"The said death is an unnatural death....Inaction will only encourage the perpetrators to roam free," the PIL said.
Pandya also said that cases of poaching of Asiatic lions in Gir sanctuary were on rise. As many as 310 Asiatic lions died in the sanctuary in the last five years, falling prey to electric shocks after coming into contact with electrified fences of farms in the surrounding areas or poaching, he said.
The wildlife crime cell of the forest department, formed after an incident of poaching in 2007, had remained largely defunct, it alleged.
A census in 2015 had showed that total number of Asiatic lions in Gujarat had gone up to 523 from 411 in 2010.