A Florida nurse told police 'I think I killed our son' after she allegedly punched the three-month-old so hard that she crushed his skull with her diamond ring.

Jessica Vlasac, 42, called 911 just before midnight on September 6 to report that her infant son August Lionel was unresponsive at her Lakeland home, according to the Polk County Sheriff's Office.

Paramedics rushed the baby to nearby Orlando Health Medical hospital, where he was pronounced dead shortly thereafter. 

Vlasac told deputies that she had accidentally fallen asleep with the baby in her bed and that when she woke up he was face down, 'not moving and cold to the touch,' police said.

But investigators claim August Lionel had an abrasion and bruising on his head. 

The infant's father told detectives that Vlasac 'becomes violent' when she drinks and alleged that she admitted to buying alcohol earlier that day, police said.

He showed investigators messages that Vlasac allegedly sent that night, 'stating that she had killed the infant and that he was dead,' according to officers. 

Vlasac was arrested last Thursday and charged with felony aggravated child abuse resulting in the death of the three-month-old infant. She has not yet entered a plea.

An autopsy report showed that the baby suffered subdural hemorrhaging around his skull, according to police.

He also had three separate injuries on his head, including one that appeared to be caused by a small, square-like object, the coroner reported.

The autopsy also stated there was no evidence that co-sleeping caused his death. 

As detectives interviewed Vlasac, they noticed a large, diamond-like stone on her ring finger that was reportedly 'consistent' with the injury described in the autopsy.

Investigators executed a search warrant and confiscated her ring and electronic devices. 

While deputies were carrying out the search, she asked if the ring was what killed her son, police said.

Officers also determined that Vlasac had 'deleted some messages' from her phone and urged her son's father 'not to show detectives their messages.'

Investigators interviewed people who were in the home at the time of the boy's death and they reported that Vlasac had been caring for him alone in her room.

They were unaware of anything suspicious until they heard her screaming, police said.

Vlasac, wearing what appears to be bright purple scrubs, was taken into custody on Thursday and booked into the Polk County Jail. 

According to jail records, she is not yet eligible for bond. Vlasac is due in court on Thursday for a pre-trial detention hearing.

Her arraignment is scheduled for October 13. 

The Polk County Sheriff's Office says their investigation remains ongoing.

The Daily Mail has approached her lawyer for comment.