Possible off market deal - what to do?

[Pat Coogan]

Friend just told me that their next door neighbor is looking to put the property on the market in the next 60 days. The owner apparently tried to sell back in 2014 and even lowered price once, but ultimately withdrew the listing. Friend knows the tenants currently occupying the property, but doesn't know the owner. 

How should I proceed? I've been interested in that particular neighborhood for a while but everything on the MLS sells within days, best and highest, usually over asking. I'd like to avoid that of course. What would you do?