The scales are tipped here. Martha Beck, who was a nurse weighing some 250 pounds and had to be squeezed into the electric chair, is now portrayed by Salma Hayek. (The late actress, portly Shirley Stoler, played her in “The Honeymoon Killers.”) Hayek is gorgeous and that lends a different element to the film, transforming the spectacle from the more bizarre into Hollywood-type casting.

The portrayal of Ray Fernandez, who with Beck found vulnerable women and fleeced them of their money before killing them, is closer to reality as played by Jared Leto. (Tony LoBianco was Fernandez in “The Honeymoon Killers.”) Regardless of casting, what the pair do is so loathsome that even though I’m absolutely opposed to capital punishment, seeing them get theirs in light of their callousness to their victims stirs a certain grisly satisfaction. ( Not shown is that two unrelated others were also executed in the same busy night at Sing Sing.)

What makes the film more interesting is the part involving the detectives. John Travolta is excellent in the role of Elmer Robinson, who was the grandfather of writer-director Todd Robinson, and the relationship is what inspired the desire to tell the story. The detective’s life is a troubled one. His wife has committed suicide, he needs to cement a relationship with his young son, and his girlfriend Rene, enacted by Laura Dern, wants to leave him because of his lack of commitment.

The other detective working on the case, Charles Hildebrandt, is played effectively by James Gandolfini, this time on the right side of the law in contrast to his renowned role on “The Sopranos” TV series, but retaining toughness, here tinged with cynical coping with reality.

The film begins on the night of the execution and flashes back to portray how the murderers hook up. Finally, Beck and Fernandez are cornered and nabbed in Michigan, where there is no death penalty, but in a deal made with authorities there, they are extradited to New York, where they can be executed.