The video shows Ferreira Cruz telling journalists through his prison window, "It was not David," and "His clothes confused me."
Ferreira Cruz told Dominican media that the people who hired him for the hit only told him the color of the clothes they were wearing.
Prosecutor Spokesman Erick Montilla responded to the media reports, doubting that a Dominican would not recognize David Ortiz, and that Ferreira Cruz invented a "story" so as not to be "lynched" in jail.
"He can say what he wants in an interview," said Montilla. "What matters is the investigation and what he said in the interview."
He added, "If you look at the video (the shootout), he goes straight to where the victim is and shoots without hesitation."
43-year-old Ortiz was in a Santo Domingo nightclub Sunday night when he was shot in the back. TV presenter Jhoel Lopez was also shot.
The Dominican National Police has previously stated in press conferences and court documents that Ortiz was the intended target of the well-organized attempt in his life.
Prosecutors have indicted eight men and one woman as accomplices.
Ortiz, known as Big Papi, is recovering and in a guarded state in a Boston hospital.