TULSA, Oklahoma - A Tulsa teen is in jail on a child abuse complaint after an eight-week-old girl was brought to the hospital suffering from multiple injuries Friday evening.

Police say Andrew Leach, 19, claimed he injured his girlfriend's daughter after getting angry, because he thought his girlfriend was cheating on him.

Investigators say the infant's grandmother noticed something was wrong and took her to the hospital.  The hospital notified police after examining the child, finding several skull fractures and bleeding on the brain.

Police say Leach admitted to investigators he had shaken the child and had hit her in the head with his knees.

Andrew Leach is not the child's father - but had been living with the baby's mother.

The infant's mother was questioned and released.  

Tulsa County jail records show Leach is being held on a $50,000 bond with a court appearance set for August 26th.