The redacted email also says it contains a picture of the license plate. How could that come from a cracked phone?
It sounds more likely that some photo based speed trap has been compromised.
It's just a link that claims to be a picture of the license plate. The link's actual target delivers malware to the device.
The malware could have some local vector, I highly doubt the police network would have that level of access *scared emoji.
I've consulted on software projects for police networks. Admin level access is easy to come by. There's a lot of trust in firewalls, once you're beyond that it can be fairly open.