"Mindless damage" has been caused to a defibrillator box in Redditch.
West Mercia Police said it was attacked at the Matchborough Centre on the evening of 29 October.
It said the damage was "a real concern to the local community as it was put in place to help save people's lives."
The force has shared some CCTV footage of some people who officers would like to speak to in connection with the investigation.
Although the image is not clear, police said they hoped the individuals' clothing or mannerisms could help identify them.