[hash872]

How did you find the freelancer's other clients? Upwork keeps that pretty locked down so that they can serve as the middleman. (Maybe you have a hack?)

[mtlynch]

The freelancer had Work Diary enabled, which took screenshots of their screen as they worked and shared them with me as their client.

From the screenshots, I could identify other projects they worked on and other Upwork accounts they were using.

[tmikaeld]

At that time, I believe you could see previous work by default, now you have to choose to share it.