A 20-year-old man from Stanmore, alongside a 25-year-old man from Dunstable in Bedfordshire, have been arrested on suspicion of conspiracy to commit burglary.
It follows “suspicious activity” reported at a premises in Clarendon Road, Watford, at around 11pm on January 2.
Police attended the scene and arrested two men – both of whom have been released on bail whilst the investigation continues.
Detective Constable Alex Humphreys, from Hertfordshire Constabulary, said: “We were alerted to suspicious activity at the premises, and our unit was quickly on site to investigate.
“We need the community to be our eyes and ears and to report anything they think doesn’t look right, and we will get units out immediately to stop a suspected crime in progress.
“If you witnessed this incident or think you have information that could help, please get in touch.
“If you were driving in the area around the time stated and have a dashcam please get in touch.
“Your footage could be important to our enquiries. Please call 101 quoting reference: 41/575/26.”
