OKLAHOMA CITY - Oklahoma County prosecutors on Thursday charged a Tulsa dentist with first-degree murder in connection with the death of his girlfriend's 19-month-old son.

Bert Franklin, 35, was arrested on July 21 in Tulsa, where he also practices dentistry at Signature Smiles on South Yale.  

A police affidavit says the incident involving Lincoln Lewis happened at his girlfriend's home in Oklahoma City earlier this month.  

The toddler first went to an Oklahoma City hospital with a suspicious skull fracture. His injuries were so severe he was flown to a Tulsa hospital where he later died. Police say doctors reported Lincoln Lewis had a displaced skull fracture when he died.

News On 6 did a story on Lincoln in November 2015. He was born premature and an artist decorated the special helmet he had to wear, to make it more personal.