Emily had been dealing with addiction issues for more than a year before her death, KELO-TV reported.
Kennecke said she was surprised to learn her daughter had been 'shooting heroin' given her middle-class upbringing.
The station reports that synthetic opioids like fentanyl are often mixed into the black-market supplies of heroin, cocaine, methamphetamine and anti-anxiety medications.
An autopsy revealed Emily had six times what would be considered a therapeutic dose of fentanyl for a large man, Kennecke said, adding that her daughter 'was just a small young woman' and 'didn’t stand a chance.'
Kennecke added that she had noticed red flags in the lead up to her daughter's death.
'Everything in my instincts told me something is seriously wrong here,' she said.
An intervention for Ms Groth was scheduled for May 19, but she tragically died on May 16.
Kennecke has set up a fund called Emily’s Hope to raise money to pay for treatment for those struggling with drug addiction.
If you, or anyone you know, is seeking help contact Lifeline on 13 11 14 or visit Lifeline.