Your only chance..... if you chose to take on this battle.... is to hire a lawyer.

Then bugs started crawling out of it and when heated up smelled like urine.

Again, I've had to edit many of your posts that smelled like recruitment posts.

By that I mean, no foul play only fair play. :).

Once the seller dies, your ownership interest becomes fee simple, meaning you’ll have complete ownership rights.One problem with purchasing a remainder estate interest is that should foul play be expected in the death of the person with the life estate the person with the remainder estate has just obtained prime suspect status.What you are proposing is making an actuarial bet, that the seller will pass quick enough for you to make a large return.

For many new investors, that's half the battle. 

Sounds to me the buyer had a problem with the wholesaler and wanted to cry foul.

You're fighting a losing battle.

Another tenant in a duplex that I kicked out (inherited tenant) because they infested the whole place with fleas ...like serious horrible fleas that had to be sprayed 4 times to treat after they moved out.....from their dirty smelly dogs ...that smelled like dirty dog the first second you walked through the foyer and they had a horrible dangerous dog that was vicious & large and go after repairmen or anyone it saw.

If house hacking (in your home market when prices are down so much) is not on the table, REI is going to be an uphill battle.