Raw Land Opportunity to be bought through tax lien.

[Clay Ickes]

There are two lots in a popular area in Colorado that were taken by the city for non-payment of taxes. I believe after the owner died, but haven't been able to confirm that. For 80k I can buy the tax lien. At that point, the person has 90 days to 'redeem' it (meaning buy it back from me), but I believe from my online research the owner passed away in 2018 with no heirs. Once no one redeems it, in a further 4-5 months clean title is transferred. Comparable nearby properties are selling for 300-500K.  I have a potential partner who has done this kind of thing before and will be doing all the leg work for a 50/50 split of profits made after the initial loan amount is paid back. 

I'm wondering if anyone has any insight into this kind of deal, knowledge about land sales, buying liens, and other relevant info. Any pieces of input or advice about how to navigate this would be very welcome!