My thought was: What "Republican congressional candidate" would have the capacity to monitor Ukraine Ambassador Marie Yovanovitch? Who could arrange to have her physical movements tracked in real time, as well as her computer & her phone use?

WTF?

Giuliani sought private meeting with Ukrainian president, documents show

The records, released by the House Democrats, also appear to show that former Ukraine Ambassador Marie Yovanovitch was being monitored.

https://www.nbcnews.com/politics/trump-impeachment-inquiry/giuliani-sought-private-meeting-ukrainian-president-documents-show-n1115691?cid=sm_npd_nn_tw_ma