The 24-year-old was shot eight times as he rode a motorcycle through the streets of the capital San Juan on Thursday.
An investigation is under way but those responsible have not yet been apprehended. Fret’s murder is the 22nd reported homicide in the country during the first 10 days of 2019.
He added: “There are no words that describe the feeling we have and the pain that causes us to know that a person with so many dreams has to go.
“This violence must stop. We must all unite in these difficult times, and ask for much peace for our beloved Puerto Rico.”
Gay rights in Puerto Rico are relatively liberal – same-sex marriage and adoptions have been legal since 2015 although public opposition still exists in some parts of the country due to the strong influence of the Catholic church.