I did it
Fi-lo escrever a carta para mim.
I made him write the letter for me.
Minha mulher não compareceu à festa, tampouco fi-lo eu.
My wife didn't attend the party, and neither did I.
Fi-lo por ela.
I did it for her.
Fi-lo tão bem que saí nos jornais.
I did it so well that I ended up in the newspapers.
Sim, fi-lo intencionalmente.
Yes, I did it intentionally.