Petti McClellan was holding her toddler Chelsea in her arms when a nurse injected the girl with a dose of succinylcholine, a powerful muscle relaxant. She was still holding her daughter when the nurse gave her choking girl a second shot.
Chelsea McClellan died in 1982 and the nurse who injected her, Genene Jones, was convicted of her murder and sent to prison for 99 years.
Because of a loophole in Texas law, Jones -- who is suspected by the prosecutor who sent her to prison of killing as many as 46 babies -– will be released in 2018.
The possibility of Jones' release has Petti McClellan, 59, of Cypress, Texas, trying to find a way to keep her in prison. It has also forced McClellan to relive the day when her daughter died.
"Jones was working at a new pediatric clinic in Kerrville," McClellan told ABCNews.com. "I remember being so excited to have a neighborhood pediatrician that I could take Chelsea and my son Cameron to."
"Cameron was about 3 years old when he got the flu so I took him into the clinic, and I brought Chelsea with me," McClellan explained. "As we sat in the waiting room, Genene said she would update Chelsea's shots."
McClellan was at first unsure if her 15-month-old daughter needed vaccinations, but said "nothing seemed strange or unusual."
"I took Chelsea and followed Genene into the examining room. I noticed that the syringes were already fixed. I was holding Chelsea, she was facing me, and Jones gave her the first shot in her left thigh. Immediately Chelsea had trouble breathing."
McClellan recalled thinking something was wrong. "Chelsea was trying to say my name, but she couldn't. I was extremely upset. But Jones said Chelsea was just mad that she was getting a shot," McClellan said while remembering that awful day.
Before McClellan could object, Jones gave Chelsea McClellan a second shot in her right thigh.
"That's when Chelsea stopped breathing," McClellan said. "Genene had this wild look in her eyes, like she was on a high. She got really excited, and she yelled that Chelsea was not breathing. She grabbed Chelsea from me and put her on a table. She told me to go get the doctor."
The clinic's doctor, Kathleen Holland, called for an ambulance.
"I was just terrified. It was a real mother's terror," she said.
Chelsea McClellan was stable and breathing on her own by the time she got into an ambulance, McClellan recalls. They arrived at Sid Peterson Hospital in Kerrville, where doctors decided to transfer the girl to a bigger hospital in San Antonio where she could be carefully monitored.
Chelsea would not survive the drive.
"When we left for San Antonio, I was following the ambulance in my car, but somehow Genene got into the ambulance with Chelsea and two other EMTs. I was driving behind him, nervous, but I knew Chelsea was stable, when all of a sudden the ambulance pulled off the highway. Something had gone wrong. Chelsea died."
"I was a mess, I just fell apart. I don't remember much from that moment."
Jones had injected Chelsea McClellan with a third shot while in the ambulance, claiming that she was having a seizure even though two EMTs in the ambulance testified that her vitals were fine, according to McClellan's attorney and Kerrville's district attorney at the time, Ron Sutton.
An autopsy could not determine the cause of death.
"In my gut, I had this feeling that something was wrong, but the doctors just told us Chelsea died of Sudden Infant Death Syndrome," McClellan said.