I was wondering if it is possible to ask someone to do something by simply using infinitive form of verb with direct object/indirect object pronoun attached and without using any other words? Or you always have to use imperative form of verb and conjugate it? I am asking because sometimes I think I can hear this infinitive form in movies (translated from English to Spanish), but I am not sure if I heard correctly. In subtitles at the same time I see always conjugated form of verb. But still, can you say the following for example:
"Matarlo, sin ruido, tengo invitados" (in subtitles, there was "Mátenlo, sin ruido, tengo invitados").
Of course, I am not asking about the following possibility: "Debes matarlo sin ruido."