Crime Man Helped Girlfriend Try to Kill Baby by Putting Crushed-Up Painkillers in Breast Milk Bottle Sir Marshall S. Snyder III was first charged in connection with the crime last summer By Chris Harris Chris Harris Twitter Chris Harris has been a senior true crime reporter for PEOPLE since late 2015. An award-winning journalist who has worked for Rolling Stone and MTV News, Chris enjoys prog rock, cycling, Marvel movies, IPAs, and roller coasters. People Editorial Guidelines Published on January 17, 2019 02:45 PM Share Tweet Pin Email The 23-year-old Indiana man accused of aiding his girlfriend in her attempts to kill her infant niece by lacing her bottle with pills has been sentenced to 15 years in prison, PEOPLE confirms. Sir Marshall S. Snyder III, 23, was sentenced Tuesday for helping his girlfriend, Sarai Rodriguez-Miranda, 20, poison her baby niece back in January 2017. In March of last year, Rodriguez-Miranda pleaded guilty to attempted murder after admitting she tried to kill her brother’s newborn daughter by lacing the infant’s milk with crushed-up pills. Snyder was formally charged in July. Online court records accessed by PEOPLE confirm his punishment. Woman Tried to Kill Baby Niece by Lacing Bottle with Pills — and Now Boyfriend is Charged He was sentenced on one count of felony aggravated battery. Court records indicate a charge of attempted murder was dismissed because he agreed to plead guilty to felony aggravated battery. Before she tried to kill the baby, Rodriguez-Miranda had been upset that her brother, his fiancée and their baby were living with her in her mother’s home, a court official previously told PEOPLE. She sent a series of texts to Snyder from a phone that she shared with her mother that revealed the plan. “I’m gonna crush up some of these pills since she decided they can stay longer and kill their baby,” Rodriguez-Miranda wrote to Snyder. • Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter. Hours after the texts were sent, Rodriguez-Miranda’s mother read the messages on the phone they shared and went to check on two bottles of breast milk in her refrigerator. She detected a powdery residue at the bottom of one bottle and the milk also appeared to be discolored. The bottle was tested, revealing trace amounts of acetaminophen (a pain reliever and fever reducer), caffeine and aspirin. A forensic toxicologist determined nine capsules of Excedrin — a lethal dose — had been crushed before being sprinkled into the milk. When the baby did not die, Rodriguez-Miranda texted Snyder about how frustrated she was. Indiana Teen Allegedly Tried to Kill Newborn Niece by Lacing Her Bottle with Pills “Why didn’t that baby die dude,” she wrote. “I hope she dies. I don’t feel bad about it bc she was destined to grow up [expletive] or be abused. I’d never be suspect I know but I hope it works.” According to court records, Snyder helped his girlfriend flee the Fort Wayne area after police started investigating her. She was sent to live with Snyder’s father in Michigan, where she was arrested months later. Rodriguez-Miranda pleaded guilty to one count of attempted murder last March and was sentenced to 25 years behind bars in May.