Help. Strangers using my garage for storage. Tenant being evicted - OH

[Marvin Michel]

Hello,

I am in the process of evicting a non-paying tenant. My tenant is currently in jail on a felony charge so he is not on the premises and marshals are going to have to come to aid in removing his personal  belongings from the apartment. On my property is a garage, access to which I gave him to store his vehicle. But over time I have noticed on security footage persons that I don't know coming in and out of my yard to use the garage for storing random items. At first, I thought they were friends of the tenant, but now that this tenant is being evicted, and with him being in jail, I don't know how to go about notifying these strangers that they will no longer be allowed to use my garage for storage. I should also add that I am a long distance landlord. My property is in OH but I live in NY.

1. What is the best, safest way to go about notifying these people that it's time to remove their personal belongings by a certain date and that all locks will be changed? I emphasize "safest" because since my tenant is clearly mixed in with the wrong crowd, I don't know what types of people his friends are. 

2. What do you recommend I do to reassert control over my property beyond changing the locks? I am thinking of installing trespass-proof gates (currently it's just a chain linked fence) and I am thinking of hiring a security company like SimplySafe of Vivint (currently I just have a self-installed Reolink and the cameras are cheap and not always functional. Can anyone recommend a good security company?)

3. Is there anything else that I am overlooking that I should be thinking about? 

Thanks for all your help

Marvin