Nineteen-month-old Lincoln Lewis’ death caught the attention of the national media when prosecutors claimed surveillance video recovered from his mother, Roxanne Lewis-Randall’s home showed Roxanne’s boyfriend at the time, Dr. Bert Franklin, before and after the toddler sustained his fatal injuries.

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On Monday’s Dr. Phil, Roxanne describes what authorities claim happened.

“Bert carried him down the steps. Lincoln had his pacifier in his mouth and he walked back into the living room area, handed Lincoln his bottle on the ground - stepped over him and walked - just a couple steps. And then he turned –and – you can see him on camera - makes a violent kicking motion that you can’t see the bottom part of his body but you can see the top part. And he walks back into the living room and got a piece of pizza, and then he walks back in the living room and picks up Lincoln and makes like a violent shoving motion to the floor. Rams him head first into the floor.”

Bert Franklin denies ever hurting the child.

When Lincoln later died at an Oklahoma hospital, it was determined by the medical examiner that he’d suffered “A non-accidental blunt-force trauma to the head.” The child’s skull was fractured. Dr. Franklin has been charged with first-degree murder. His trial is tentatively set for September 2017.

What more does the grieving mother say about the night Bert Franklin allegedly caused her son’s fatal injuries? And what’s happened?

Tune in to Dr. Phil’s exclusive interview with Roxanne Lewis-Randall on Monday. Find out where you can watch here.

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Mother of Fatally Injured Boy Claims Her Boyfriend ‘Just Stared’ At Her When Told To Call For Help