I have an ex-student who has applied for multiple places and got called for interviews like about 10s of times.

There was this company who called him back after 2 months from his last interview with the Hiring Manager and HR.

I find it a bit weird. He asked them why the delay and since he has found a job, he may want to stay put there.

The HR there explained that the process is taking longer and bla bla bla.

What do you guys think could be the real cause for such delay?

But how you found out?