If the successful bidder assigns his interest in any real property purchased at the Delinquent Tax Sale before the end of the redemption period, the grantee from the successful bidder shall furnish the Tax Collector with a conveyance, witnessed and notarized, a copy of the bid assignment form may be obtained from the Tax Collector's Office.Bidder checks (for the bid amount plus interest) will be mailed to the successful bidder, or their grantee, once a property has been redeemed and funds have been verified by the Tax Collector and pay periods have been determined.

Tell them that this is a constant problem and you are at your wits end as to what to do. 

First lien does not get affected they can only get what they are owed.So while I can see how you thought this was cool.. it certainly is not and its highly illegal.. and if I was there and I was bidding and witnessed this activity I would file a complaint with the DA and FBI

@William Hochstedler  were I saw this model fail miserably for LA based investors was even though they are full doc.. the cash reserves that are there at the beginning.. investors get this irrational sense of security that their rents are going to come in like clock work that the homes are going to stay rented that their home will be taken care of like they would.. and the reserves end up getting spent on other things in their lives.. thereby wildling down their reserves.YOu have a bad run... you need 5k to fix up and re rent... house is vacant for 3 month during the process... and if you don't have the funds your PM is noting going to front it for you.. and down the tube you go. that's what I witnessed.. these were not speculators  these were people that thought their 100 to 200 a month positive were a given and could never change.. and they were woefully under capitalized. 

The land trustee then becomes a second set of eyes and ears (and a more credible witness when saying a deed was forged), preventing/reducing title theft. 

Anecdotally, I witness much frustration in the mortgage industry.

This gives you an objective third party as a witness and it ensures the charges stand up in court.What you experienced is very common in real estate investing.

Quote from @Wesley W.: It will not surprise anyone to know that NY requires landlords to accept a credit report from any applicant that is less than 30 days old. 

Or in Greece where Judge's can call there own witness's and defend the best interest of the kid's as matter of national/state importance. 

Go there with a witness, hand squatter the 30 day notice to vacate with his name on it, the more information on paper Larry Immediate Carpet 17007 Laverne Ave Cleveland OH 44135  or 3275 W 46th St, Cleveland, OH 44102 Phone: (216) 256-6698the better.