A 73-year-old man died after the incident while two other men in their 60s and 70s were sent to hospital to be treated for injuries.
Three men have been arrested on suspicion of gross-negligence manslaughter after a fatal bridge collapse during a shooting trip on a farm in Lancashire.
Brian Harwood, 73, died after an all-terrain vehicle and the trailer it was pulling plunged into a river in the Moor Lane area of Roeburndale on Tuesday.
Police were called at around 4.25pm following reports of a serious incident on a farm and Mr Harwood was pronounced dead at the scene.
Two other men in their 60s and 70s remain in hospital receiving treatment for injuries sustained in the collapse, the force said on Thursday.
Detective Inspector Mark Dickinson, of Lancashire Constabulary’s Major Investigation Team, disse: “This investigation remains in its early stages and we are conducting a number of inquiries to establish exactly what has happened, including whether any criminal offences were committed.
“Three men have been arrested and are assisting police with our inquiries. They have now been released, but remain under investigation.
“We are supporting the families of those involved and working with partners, incluindo o Health and Safety Executive to establish what caused the bridge to collapse.
“Our thoughts remain with Mr Harwood’s loved ones and everyone affected by this tragic incident.”
Anyone with information about the incident can contact police on 101 quoting log 0953 of January 18.