Two men died at a farm near Bottesford after reportedly becoming trapped in a slurry tank.
The men, aged 19 and 35, died at Church Farm, in Normanton Lane, Normanton, on Thursday.
Leicestershire Police officers are carrying out enquiries on behalf of the coroner.
The names of the two men have not been formally released by police but they are believed to be from the Grantham area.
Police officers were initially called to the farm at around 4.30pm on Thursday, joined by fire crews and paramedics. A fire crew from Bingham and four crews from Nottingham and Leicestershire attended the incident.
Unconfirmed reports suggest that the men were trapped inside a slurry tank and firefighters attempted to rescue them by cutting through the side of the tank.
Investigating police officers remained at the farm throughout the night.
Post-mortem examinations are yet to be carried out to determine the cause of death.
The Health and Safety Executive (HSE), a public body which investigates workplace incidents, confirmed it is also conducting an investigation into what happened at the farm. A spokesman said the incident is believed to have involved a delivery of slurry to the site but said it was not known how the men “came to be exposed”.
The spokesman added: “We are investigating alongside the police.
“We started investigating on the scene the following day.
“The police will make sure there is no foul play before formally handing over the investigation to us.”
It is believed the HSE will take over the investigation this week.
A company called Green Feeds Ltd operates from the farm, where it produces animal feeds from dry and wet ‘co-products’. The company’s website says it can separate, crush and recycle almost any product from its original packaging.
The company says it operates every day of the year and has its own haulage and tanker fleet.
When approached by this newspaper, a spokesman said Green Feeds would not be making any comment.