Human remains discovered at a depot may have got there after being chucked in with a recycling collection, police have said.
A police cordon remains in place at a recycling plant where the body parts were discovered yesterday.
Specialist officers are carrying out investigations at the site after Avon and Somerset Police were called to the plant in Avonmouth, Bristol, where workers made the gruesome discovery of male body parts yesterday morning.
The area was cordoned off and police have launched an investigation.
Police are now focusing their inquiries on Swindon after it is believed the body parts may have come from a recycling collection in the Wiltshire town, about 45 miles away along the M4.
Senior investigating officer Gareth Bevan, said: "Police enquiries so far suggest the body was transported with commercial recycling waste collected in Swindon and therefore the focus of the investigation will be in that area.
"The investigation is at an early stage and we are keeping an open mind about the circumstances leading to this man's death."
Police said they were called to the scene at around 11am yesterday. Employees at the site were concerned at what they thought were remains at one of the units.
Officers cordoned the site off.
Police confirmed the remains are believed to be male, but that it was too early to say how long the body parts had been dismembered.
The victim has yet to be identified, police said.