sorry, it is a holiday in Colombia, but I try to contribute with some information to your question
While you may be able to buy real estate in Colombia with just a tourist visa, getting a loan or mortgage to finance a purchase is another matter. It has been extremely difficult for foreigners to get a mortgage from Colombian lenders. For this reason most property purchases by foreigners in Colombia are done with cash. It is even difficult for Colombian citizens to get mortgages.
To even be considered for a mortgage as a foreigner in Colombia, you will need to have residency and have lived in Colombia preferably for a few years. You also need to have a bank account in Colombia and a credit history in Colombia and may also be asked for proof that you pay taxes in Colombia. In other words, you need to be well established in Colombia before banks will even consider lending to you. I only have met one foreigner that was able to get a mortgage from a bank in Colombia and he is married to a Colombian, had banked in Colombia for several years and had paid taxes in Colombia plus was going to live in the property. He also had to provide a ton of paperwork to get the mortgage.
so to my own feeling, it is better to get it from the USA
thanks