First Apartment purchase, advice needed. 12 unit

[Michael Hutchinson]

All, I am looking at buying my first apartment building, assuming my research works out this weekend.  I would love to get general advice to look for, resources, etc. to help make sure I evaluate this correct.  Here is the overview:

• 12 unit property (3 singles, 6 two bedrooms, 3 three bedrooms)
• Being sold from investor (red flag for me)
• I am using rentometer.com to estimate rent prior to first meeting.  That tells me I should get:  $500, $700, $900 for the units approximately.
• Building is being sold for just over $400k (second red flag)

I feel like I have a reasonable understanding of single family, but this would be the first time that I have considered this type of investment.  I am curious on things like regulations to look for, normal required services (i.e. trash), security, etc.  Any help thinking this through would be appreciated as I don't know what I don't know.  :)  Thank you!