Wiltshire Police are currently excavating gardens in Swindon town centre.
The gardens are said to be linked to murderer Christopher Halliwell.
The operation, on Broad Street, is expected to last a number of of days as police search two properties believed to be on the same street following intelligence the force has received.
“Specialist officers are currently carrying out excavation work within the gardens of two properties within Broad Street as part of an ongoing investigation being carried out by the Brunel Major Crime Investigation Team.
“This relates to intelligence that the force has received.
“We are unable to comment further at this time.”
Halliwell, a former taxi driver in Swindon, was jailed for a whole life term, after being found guilty of murdering Becky Godden while he was already serving a life sentence for the murder of Sian O’Callaghan in 2011.