Houston ( CNN ) -- Back in 1982 , Chelsea McClellan -- just 15 months old -- needed immunizations . It was routine stuff , so Chelsea 's mother took her to a local clinic in Kerrville , Texas . What happened there was anything but routine . That 's because Genene Jones was the nurse on duty . Chelsea 's mother recalled the day . `` She gave her her first shot in her left thigh and she immediately started gasping for air , '' said Petti McClellan-Wiese . `` Gave her another one , and she immediately just went limp and quit breathing . '' In the chaos of rushing Chelsea from the clinic to the hospital , Jones somehow slipped into the ambulance and gave the little girl a third shot . McClellan-Wiese would learn later that the nurse had injected her daughter with a drug called Succinylcholine , which causes muscle relaxation and short term paralysis . It stopped Chelsea 's heart . Jones was convicted of infanticide and sentenced to 99 years in prison for killing Chelsea , plus 60 years for injuring another child . She maintains that she did nothing wrong . For Chelsea 's parents , the verdict was bitter sweet . Their daughter was gone but her killer would spend the rest of her life behind bars . At least that 's what they thought . But it turns out , Jones is set to walk free in a matter of a few years . She is scheduled to be released from prison as early as May 2018 because of an old Texas law designed to prevent prison overcrowding . The Mandatory Release law allows inmates convicted of violent crimes between 1977 and 1987 to be automatically released if their `` good behavior '' credit plus their time served equals their sentence . The law was changed in 1987 to exclude violent criminals , but it is n't retroactive . So now McClellan-Wiese and Andy Kahan , a victim 's advocate for the city of Houston , are desperately trying to find other mothers whose babies may also have been killed by Jones . A new conviction could keep her locked up . Kahan says that two mothers have already reached out to him , including Marina Rodriguez . Rodriguez lost her son in 1981 after , she says , Jones gave him a shot at a San Antonio clinic . At just 5 months old , he had a heart attack and died . `` All of a sudden he turned blue , and all of a sudden , I started hearing code blue . And then of course they put me to the side because I 'm a young mommy and I 'm freaking out , '' she said . Back then , Rodriguez was 15 years old . She could n't read and was too young to afford a lawyer . Her parents were migrant farmers . When asked how she would feel if Jones were to walk free , she said she could n't contemplate the possibility . `` She 's not getting out ! She 's not going to get out ! If my son has to be exhumed to prove that she murdered him , then that 's the step we 'll take . They 're not dealing with a little girl anymore , this is a woman now , '' Rodriguez said . Watch Anderson Cooper 360° weeknights 10pm ET . For the latest from AC360° click here .
Mary Jones , a nurse , was sentenced to 99 years in prison for killing a year - old . She maintains she did nothing wrong . Jones will be released early because of an old law designed to prevent this .