If the police seized it, it would be considered evidence and I wouldn’t get it back until after the trial, which could take months to resolve.

She wanted her stuff back sooner rather than later. What's unclear to me is the bit about the trial -- was the thief caught and brought to trial? Or is she talking about a proceeding based around seizing the property?

Sounds to me like she might have been coached by the detective into resolving this outside of the law, and I'm not sure who that benefits.