Impressive procedural skin crawler.
It's a very impressive film from start to finish, the cast are excellent, George Kennedy & Henry Fonda portray the men pursuing the culprit with much believability, with enough moments of frustration and revulsion brought to life with style.
Of course this is Tony Curtis's show all the way, though, he is all bulked up and nothing like the handsome icon that people had grown accustomed to. He is convincingly menacing and handles the dual personality confusion scenes adroitly. One of the films' chief plus points is that the first hour only shows us the aftermath of the murders, it shows the desperate panic it creates among the people of Boston, and of course we get to know the detectives following this miserable trail.
At the hour mark we are introduced to Tony Curtis as Albert De Salvo, here he is in his family home, his daughter all radiant around her father, it's a masterstroke from director Richard Fleischer, and it creates maximum impact. The use of multi screens to show various aspects of scenes is deft and manages to make the film seem all too real, which of course is given weight of impact since it is based on actual events.
Smashing film that gnaws away at the skin some time after the silent credits have rolled. 9/10