Cleveland Police have released recordings of the moments after stunned officers arrived at a house where three women had been held captive for 10 years.
In the recordings one of the first medics arriving at the scene after Amanda Berry, Gina DeJesus and Michelle Knight escaped can be heard telling colleagues in a shaking voice: "This might be for real."
The exchanges over the emergency services radio system came after Amanda Berry escaped and called 911 while alleged captor Ariel Castro was out of the house on Monday.
An operator is initially heard calmly relaying the details of Ms Berry's call to colleagues, telling them: "I have a call taken on the phone with a female that says her name is Amanda Berry and that she has been kidnapped 10 years ago.
"She's saying that the male is Ariel Castro, 52-year-old Hispanic male that lives at 2207 Seymour, and he's been holding her here for 10 years."
Soon after - with a panicked female voice, thought to be Amanda Berry, in the background - an officer says: "Adam 23, you got a box comin'? This might be for real."
As the distraught woman starts telling her story, the same officer says: "There might be others in the house ... Georgina DeJesus might be in this house also."
The next voice audible on the recording is from one of the first officers to arrive at Castro's house.
With the sound of a woman crying clearly audible over the police radio, the breathless medic tells dispatchers: "We found 'em ... we found 'em."
The next caller from inside the house says: "We got a female called Sabrina (sic), she's got a young child with her."
As the officers move through the house and discover the scale of the crime, they discover a second adult female and radio through to say: "Make it two."
A colleague adds: "We also have a Michelle Knight in the house ... you wanna look that up in the system ... 32-years-old."
Ariel Castro has been charged with kidnap and rape in connection with the women's imprisonment.