State/county specific question. cook county Illinois

[Robert D.]

State/county specific question. The property is located in cook county. I purchased the property on the Sheriff’s sale. I am not 100% sure if the current owner lives there. I peeked into the mailbox and the mail is addressed at current owner. I talked to the guy but he refused to provide  his name. I think we will need to start eviction. I believe I need to give him 90 day notice and then file for eviction. Does anybody know how to serve so that the judge does not throw it away on technicality ? do I need to have a name of at least one person of whoever lives there ? Can I just put on the 90 day notice “all unknown occupants”? Do I need to serve him in person or mail the notice or stick to the door ?

I have OAS that lists current owner to be evicted by the Sheriff. Problem is that sheriff will not evict anybody else who is not on the OAS. I do not want to waste time so I was thinking that if this person who lives there is the owner, Sheriff will throw them out. If he is NOT the owner then sheriff will show up and some point in 4-5 weeks and will not throw him out ..but the 90 days are already running. I would appreciate any feedback from somebody who has done in the past.

If somebody knows an attorney that does this type of evictions, please let me know.