A security company had keys stolen from one of its vans in Peterborough, with the van also being taken.
The van was owned by Dardan Security which has a base at Pinnacle House, Newark Road.
The theft occurred on Sunday evening, August 13, in Empson Road, Fengate.
However, police said it was not possible for the thieves to identify which buildings the keys would be used for.
A police spokesman said: “We are investigating the taking without consent of a van and a theft from that van which happened in Empson Road, Peterborough, at about 7.45pm on Sunday (August 13).
“Anyone who was in the area at the time and thinks they may have seem something significant should contact police on 101.”
A spokeswoman for Dardan Security said: “We can confirm that on the evening of Sunday, August 13 2017 a Dardan Security mobile patrol vehicle and driver were involved in an incident.
“We work to British Standards and these have not been compromised.
“We are working closely with Cambridgeshire Constabulary and our customers. Therefore, due to the ongoing criminal investigation, we cannot give further details at this stage.”
Peterborough City Council has been affected by the thefts.
A council spokeswoman said: “We are aware of the incident and have been assured by the security company that there is no way the people who took the keys can identify the buildings they are associated with. We will continue to liaise with the security company and the police to ensure this remains the case.”