Need advice for video monitoring at apartment complex

[Dennis O'Loughlin]

We recently purchased a 6 unit complex that was full and had "good paying tenants."  Unfortunately we have discovered that the guests of a couple of tenants were not being upstanding citizens and got themselves in trouble with the law.  

One of the tenants we have already started eviction proceedings against due to non payment of rent and the other one we are giving 30 day notice to because they had someone living with them that was not listed on their lease and this person was involved with some shady things so since it was a lease violation, she gets a 30 move out notice.   

We want to put up signs and get cameras set up around our perimeter and inside the common areas for added piece of mind for us and the remaining tenants.  Our question is, has anyone had issues like this?  What type of system did y'all have installed?  Any thoughts on which way to go because we don't need the break in alarm but we definitely want video cameras to try and encourage the people doing rotten things to stay away.