I work in a small (~25 FTE) ICT company related to energy infrastructure in Germany, Europe. I've recently been promoted to Department leader due to the people above me moving on, and thus have started getting involved in the hiring process.
Early this year, we hired three new people. One of them displayed very poor work ethic (constantly on the phone, showing no initiative on their own...) as well as a severe lack of skills:
They had supposedly finished a course in Electrical Power Engineering, as well as published a research paper on State Estimation in electrical grids. They didn't know Ohm's law, and when asked "What's a Transformer?" they started talking about AC/DC conversion. According to the documents, they studied at the same university as I had, in roughly the same time frame, taking most of the same courses. I can personally attest that the professors there do not hand out grades for free. So, after about a month of experiencing this as their new boss, I decided to let them go, suspecting a case of fraud, but deciding not to pursue legal steps. Before making the decision, I sat down with them and another senior colleague working on the same topics to try and work out a way forward, which was ultimately not fruitful.
Sidenote: I even checked and compared their signature towards what was on their drivers license - turns out they signed in block letters, literally the only person I ever saw doing that, and making forging a signature easy.
Another case came in recently for an interview. They had programming in C/C++, Pascal and Python on their resumé, did a bachelor in telecommunication and ICT, and were currently working on their master's thesis on a battery management system for electric vehicles, some eight weeks into the thesis. They couldn't explain what a Battery Management System actually does, and when asked 'Which compiler/development environment are you using?', they didn't seem to know what I was talking about, i.e. what a compiler even is. They also didn't display any other skill in the fields they supposedly studied in.
A third case, this time for an internship, went really well and they knew their stuff brilliantly, especially for someone who's just applying for internship. When we offered them the position, they declined, saying they found something elsewhere, 'But my twin sibling is looking for an internship in the same time frame'. We invited the sibling to send over their CV, we'll see how they do.
We checked all of the CVs and degrees as well as we could, but did not see them to be fake. We called former employers and found that the story matched what we read in the CV.
So, the questions would be: Is there some kind of fraud scheme going on, akin to letting your sibling "borrow" your degrees to apply at a position? Think of it as an imposter, in which case the impostee went along with the process.
Is it legal for me to call up the university and ask about a degree that I suspect to be fraudulent?
Update: To clarify, I'm not saying they all had identical twins. But the only pictures one gets with the names is the one on the CV, and possibly a picture on their drivers license/ID (though we don't routinely check a person's ID when they come in for an interview - might have to change that). Those pictures are usually several years old, and in that case it's very easy for someone to pass as their brother/sister.
I also updated the questions to clarify where I was going.