Experiment in Terror (1962) on Netflix

A man with an asthmatic voice telephones and assaults clerk Kelly Sherwood at home and coerces her into helping him steal a large sum from her bank.

When the bank clerk Kelly Sherwood arrives home after hours, she is intimidated by a stranger that knows her routine habit. He threatens Kelly and her sister Toby to force her to heist $100,000 from her bank; otherwise he will kill her. Kelly does not see his face but notes he is asthmatic. Kelly succeeds to lure the criminal and contacts the FBI agent John 'Rip' Ripley that advises Kelly how to behave and assigns a group of agents to keep Kelly and Toby under surveillance. But when Toby is abducted by the stranger, Kelly tries to stay calm to help the FBI to catch the criminal.

—Claudio Carvalho, Rio de Janeiro, Brazil

San Francisco bank teller Kelly Sherwood returns home one evening to be assaulted, her attacker who, in his threats, knows all about her - her movements and that of her teenage sister, Toby. Those threats include killing her and/or Toby if she contacts the authorities or doesn't carry out his plan for her, the details for which he will relay in subsequent contacts: rob her bank of $100,000, he "kindly" cutting her in for twenty percent. Through this ordeal including subsequent contact, she is never able to see his face, but she would recognize his distinctive voice, with its labored breathing, like he is asthmatic. In she telephoning the FBI, Kelly discovers that her attacker is indeed monitoring what she is doing in cutting off the call before she is able to provide them with any information, this her only one strike allowed. Regardless, FBI Agent John Ripley is able to follow up to discover what is going on with Kelly seemingly without her attacker knowing. Thus begins a cat and mouse game between Ripley and Kelly's attacker, any mistake by Ripley or his team which would put Kelly and/or Toby's life in mortal danger.

—Huggo

Kelly Sherwood is terrorized by a man with an asthmatic voice who plans to use her to steal $100,000 from the bank where she works. He threatens to kill her teenage sister Toby, if she tells the police. However she manages to contact F.B.I. agent Ripley.

—Will Gilbert