Your situation is not the same as cccmedia's and not the same as mine. But I have a hunch that you'd be liable for taxes as a tax resident in Colombia (if you spend 183 days or more in-country in any 365 day period you are considered a tax resident).
I used the same firm as did cccmedia for a paid opinion, not gratis - and although I pay little or no tax in the US, I would be subject to paying tax on my income in Colombia.
The best I could hope for is to be able to deduct the amount of US taxes I paid from my Colombian tax bill - and the Colombian marginal tax rates start at 19% on as little as about $1000 USD per month, 28% on everything over about $1700 USD per month and topping out at 33% for everything over about $3400 USD per month.
The law firm is
http://langoncolombia.com/