She received a devastating phone call from police after her daughter’s body was found in the early hours of Sunday.
Ms Martin said:
“(I’m) horrified. It’s something that no one could ever imagine. It’s unbelievable.”
Police are still investigating, and a post mortem was scheduled to confirm the cause of death.
Ms Martin, from Chicago’s West Side, said her daughter’s friends called her at 4am on Saturday to tell her that she was missing.
The worried mum went to the hotel but was unable to find her daughter. She asked staff to check CCTV and was referred to police, so she called 911.
Dispatchers told her to wait a few more hours because she could have been out with friends, WGN reported.
Ms Martin returned to the hotel in suburban Chicago to search for her daughter again, and the teen’s sister filed a missing person report at about 1.30pm on Saturday.
Police said hotel staff conducted a search and Miss Jenkins’ body was found just before 12.30am on Sunday.
The freezer had been turned on and was cold but was not being used to store food, the Chicago Tribune reported.
But Ms Martin refuses to believe that her daughter entered the freezer on her own.
“Those were double steel doors, she didn’t just pop them open.”