I was contacted by an HR person or recruiter first and then contacted by the actual department I was interviewing with. I interviewed with two people in the department and then came back and interviewed with the head person in the building. The people were not friendly at all but the job sounded interesting. I took the job but it was a huge mistake. Make sure you like the people you are working for because no matter how interesting the job is, it will not be a good situation if you don't get along with your managers!