There are 2 police certificates in Peru:
antecedentes policiales: you have to go to central police station in San Isidro, they will fingerprint you, make pictures, verify your teeth and so on (more deep than doing the interpol).
antecedentes penales: you go to poder judicial in centro de Lima, they will register your request, take a picture of you and finger print and then print it for you
Both require filling a form and paying in advance at banco de la nacion. Do not forget to apostille them, THEN also translate them IN LIMA, and then apostille the translation again IN LIMA! Otherwise they will be of no use for you outside of Peru.
I would get both if I were you. And get always 2 copies of that (need to pay 2x).
When I did the first one, they checked me and printed the certificate (it then needs to be signed by the Coronell of the station and takes about 1 week) and idk why but my face was looking strange when I saw "no registers crimes" and the guy doing the task looked at me and said: "hm, not happy that you have nothing on file? Oh we can put something beautiful there if you like!" and so I said "oh, if you could put mass assassin and serial murder that would be fine for me, otherwise you are not respected in this country!" - that made their day....