Driving without the owner of the car present

I am currently travelling in Columbia with 2 friends. The car we are driving was bought in Chile. When the car was purchased all the paperwork had to be put under one of our names (naturally).

The friend who legally owns the car has now gone a seperate way, leaving me and my friend with the car. Columbia roads are full of police stops and I am nervous about how they might react to our situation.

Can anyone please advise?