On Saturday, Hathras police said it was also probing into the suspected funding of the congregation.
Self-styled godman Bhole Baba's lawyer AP Singh alleged on Sunday that witnesses told him some people opened cans containing a poisonous substance in the crowd during the July 2 Hathras 'satsang', triggering the stampede.
Addressing a press conference in Delhi, Singh also alleged a conspiracy, which he attributed to Bhole Baba's "rising popularity", behind the stampede.
The stampede after the 'satsang' of self-styled godman Surajpal alias Narayan Sakar Hari alias Bhole Baba in Uttar Pradesh's Hathras left 121 people, mostly women, dead.
"Witnesses have reached out to me and said there were 15-16 people carrying cans of a poisonous substance that they opened in the crowd. I have seen post-mortem reports of those killed and it showed that they died of asphyxiation and not because of injuries," Singh claimed.
Alleging a conspiracy behind the stampede, he said, "There were vehicles parked at the site to help the men escape. We have proof and we will submit it. This is the first time I am speaking about it." Singh claimed the witnesses who reached out to him requested anonymity. "We will demand security for them." So far, nine people, including key accused Devprakash Madhukar, have been arrested in connection with the stampede.
On Saturday, Hathras police said it was also probing into the suspected funding of the congregation by a political party and warned of the "strictest possible" action against it.
Madhukar was the main organiser and fundraiser of the 'satsang' where more than 2.5 lakh people had gathered, much beyond the permitted limit of 80,000, officials had said.
The godman was not mentioned as an accused in the FIR lodged at the local Sikandra Rao police station.
The judicial commission set up by the Uttar Pradesh government will speak to anyone required for its inquiry, a probe panel member said when asked if Bhole Baba would also be questioned.
The commission will also issue a public notice soon, asking locals and witnesses to share any evidence related to the stampede, along with their statements, another member and chairperson of the panel, retired Allahabad High Court judge Brijesh Kumar Shrivastava, told reporters in Hathras.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)