PORT ST. JOHN, Fla. -

Tonya Thomas had two times the legal limit of alcohol in her system when she shot and killed her four children and herself in May, according to autopsy reports released this week.

Local 6 news partner Florida Today reports the 33-year-old woman from Port St. John had a blood-alcohol content of 0.16 percent, according to the reports, which is twice the legal limit to drive in Florida. Investigators say based on the information in the reports, they will now close the case.

“The legal limit is .08 (percent),” said Dr. Bruce Goldberger, a professor and the director of toxicology in the Department of Pathology, Immunology and Laboratory Medicine at the University of Florida College of Medicine. “She’s twice the limit. Obviously she was impaired by alcohol at the time of this event.”

Toxicology experts said that level of alcohol in Thomas’ system may have played a role in the shootings. Goldberger said such a high alcohol level likely would impair someone’s judgment and ability to process information, as well as physical abilities.

“It does reduce normal inhibitions, maybe that played some role in this as well, that in a sober state she may not have done this action,” he said. “She was more free to act out.”

Within 36 minutes early May 15, 19 gunshots were fired at a home at 7245 Bright Ave. During that period, three of Thomas’ wounded children showed up on a neighbor’s doorstep before being called back home by their mother, police said.

Deputies  said Thomas used a Taurus .38-caliber revolver to shoot and kill her children Joel Johnson, 12, Jazzlyn Johnson, 13, Jaxs Johnson, 15, and Pebbles Johnson, 17, before killing herself. Joel was shot five times and was found next to Jazzlyn, who was shot seven times, in the home’s entry; Jaxs was shot three times and was found in the living room of the home; and Pebbles had been shot three times and was found outside the home. The autopsy report says Pebbles likely collapsed when returning from the neighbors.

According to the report, Thomas was found dead of a gunshot to her head on a couch, the gun still “clutched” in her hand. Brevard County Medical Examiner Dr. Sajid Qaiser performed the five autopsies in the two days after the killings, Florida Today reports. The children appeared healthy and had no drugs in their blood, according to the reports. He found nothing unusual or out of the ordinary during the examinations, except for Thomas’ blood alcohol level.

“At the time she died, she had approximately 10 drinks in her body,” he said. One drink is about 0.03 percent BAC in a 130- or 140-pound woman, he said. Autopsy reports say Thomas weighed 197 pounds, which Goldberger said would mean one drink equal to about 0.015 percent.

He said it’s not unusual for people who commit suicide or kill others and themselves to have drugs or alcohol in their system at the time.

“It’s not unusual that they consume alcohol and or drugs to cause an intoxicated state to reduce their normal inhibitions,” he said. “This way they can act out, and often times they act out irrationally.”

Though the results provide some clues into the situation at the Port St. John home that morning, they don’t answer the question: Why did she do it?

“We’re not going to know the answer to that question, because she’s deceased,” Brevard County Sheriff’s Lt. Tod Goodyear said. “She’s the lone person responsible for the deaths.”

Goodyear said investigators will now close their case.

“Everyone understands the magnitude of it,” he said. “It’s a terrible thing when a mother takes all of her children’s lives.”