Mortgage company to redeem a tax prop. In AL, but is not listed.

[Jenny Craig]

I purchased a tax property in Birmingham al (Bessemer-Jefferson div) and recorded it on 8/7/2017. The original owners have passed away, but I have received a number of letters saying they were going to redeem, including a letter from the two dead owners. I have replied to all letters including a mortgage company that claims they have rights to redeem but when I went to the tax assessor to ask if they had a lien I was told there was no record of them.  Fast forward to November of this year,  the same mortgage company has gone to the probate court and was given the right to redeem, how is this possible? When does a mortgage company have the right to redeem? Can they be sold a mortgage and not record anything at the county level?  If they are sold a mortgage do they automatically have rights to the property? How do you find out if they are actually a lienholder?

Thank you 

Jenny