Hi all,
Yes, it could have been an >illegaly< modified ham tranciever. (Such are type accepted but ONLY for the Amateur Radio service so such use is illegal.)
Also, in many places a ham receiver >used for< monitoring police transmissions is illegal. That's where many hams are confused, as of August 20 1993 ham receivers CAPABLE of receiving police and other emergency services were exempted but the declatory ruling by the FCC makes no mention of USE. Therefore, a receiver capable of such reception falls under federal preemption but one used for it does not, all state and local laws apply.
Here's a twist, scanners. Many hams use scanners for auxilliary receivers so one programmed exclusively for ham reception is also exempt but one programmed for emergency services is not regardless of whether or not it also is programmed with ham frequencies. Yes, a scanner is obviously capable but again it's use that counts.
The bottom line is what it's used for, not what it's capable of that makes it legal or illegal. FYI, the word that fits is "intent" and you'd be surprised how the legal eagles use it to hang you. For example, a CBer may not even own a power amplifier or illegally modified rig, that is even if it's not connected, just sitting in a closet. The FCC will bust his britches because of that little word, the law assumes intent (the intent to use it).