I have a few questions about handling this situation:- should I hire and pay for a plumber to go into their unit to cut open the ceiling and identify the source of the leak? 

If not then need to hire a builder 

BP is a great source of information, and at times, of misinformation.

We hired individuals with construction and renovation backgrounds to inspect the work of our project managers in an attempt to catch flaws before listings hit the market.

Should probably look into hiring some property management too - if you have cash flow but unbearable headaches of managing - might be better to break even and hire full-service management and then re-evaluate down the line

In some situations, it may make sense to hire a pro to get the job done quickly and correctly, then you can rent it out earlier and offset the additional cost, or at least part of it.My first house took me six months to renovate.

They mentioned that this is something that they informed the previous landlord about and they flat out said that they wouldn't fix it. 

The best accountants and CPAs will be able to offer you a secure document transfer system in order to keep your sensitive information safe, and also be able to conduct their bookkeeping and tax return services electronically as well, saving both time and money.In my personal ventures into real estate, I have started several LLCs and would be happy to share my real estate experiences with you.

More importantly, insider information is really not legal, so how ethical do you think someone is that is like "hey I got a good tip on XYZ, lets invest and make $".

The information contained in this post is not to be relied upon.