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A Belle Chasse woman who fatally poisoned her toddler last year pleaded guilty to manslaughter Tuesday and was sentenced to 40 years behind bars.

Erika Wigstrom, 22, told authorities she injected hand sanitizer with a high alcohol content into the feeding tube of her 17-month-old son in January 2014.

An autopsy of the baby, Lucas Ruiz, who had Down syndrome, determined he died of acute ethanol intoxication. His blood-alcohol content was about 0.28 percent, or more than three times the limit for which drivers are considered legally drunk.

Wigstrom, who had been charged with first-degree murder, also confessed to injecting perfume into her baby’s feeding tube in October 2012 as he was awaiting open heart surgery at Ochsner Medical Center in Jefferson Parish — an incident he survived.

She told detectives she had searched the Internet to determine how much alcohol “was needed to cause someone to die,” according to a news release from Plaquemines District Attorney Charles Ballay.