I was invited to the office after a call from a project manager. I met with two group leaders and one principal in the interview. It was really casual. I got the offer. However, the company was very unprofessional. They pulled the offer all of a sudden. They said they expected me to come earlier but the day they pulled offer was only two days after the working visa petition was submitted. I did my best to get myself prepared for the move and they suddenly asked me not to go.