Three men ran off after being spotted by a neighbour as they tried to burgle a flat in Berkhamsted.
The offence took place at around 6.10pm on Friday (March 10) at a property in Pheasant Close.
The men were seen climbing on the gas box beneath the window to a first floor flat.
They climbed up to the window and attempted to prise it open, but were spotted by a neighbour who shouted over to them - at which point they ran off down the hill.
The three men are said to be aged in their late teens to early twenties. One was wearing a dark beanie style hat.
DC Chris Phillips, at the Hemel Hempstead Local Crime Unit, said: “I’m appealing to anyone who witnessed the incident or anyone matching the description of the men in the vicinity of the road between 6pm and 7pm that evening to contact me.”
Anyone with information is asked to contact DC Phillips via the non-emergency number 101, quoting crime reference D2/17/263.