I think in this context it means the same thing as the verb “probe”.

As far as I am aware, this is not a common usage, and you could go a very long time before you encounter it again. Next time you encounter it will probably be on Hacker News.

Edit: After thinking about it some more, I believe probe and interrogate are closely related. Essentially, an interrogation consists of a number of probes for the purpose of discovery. Normally, we think of an interrogation as being verbal, but in this case the interrogation is physical and consisting of a series of probing movements.

In a typical verbal interrogation, the investigator or detective will ask probing questions.