Three rounds of speaking with partners and associates in the firm, the third round was 3 hours with back to back calls, and then a final phone call with a partner

Applied online and was contacted by a recruiter via call about a week or two after. Had a phone screening for 30 minutes. Was invited in for a 2 hour interview at the DC office. 2 weeks later I hear nothing, even with 3 follow-ups. Finally get a call and was told I was given a conditional offer, pending the salary negotiation + background check. In the middle of salary negotiations (a series of back and forth calls with the recruiter), I was told via email that the team rescinded the offer. When I asked the recruiter what the reason was for rescinding, because I felt that I was owed an explanation, she said "the team didn't provide a reason. apologies" . Unprofessional and terrible.