TAMPA, Fla. (WFLA) — In 2017, Plant High School senior Katie Golden died of a drug overdose.

Last week, Garland Ryan Layton, 38, pleaded guilty to manslaughter for selling her the drugs and will now serve 10 years in prison.

Hillsborough County State Attorney Scott Harmon says it’s a groundbreaking case in many ways.

“This case really led to the evolution of the opioid task force that we now have with the Tampa Police Department and the Hillsborough County Sheriff’s Office,” said Harmon.

Golden’s father says that he and his wife are thankful the case is now over, but the last five years have not been easy for them.

“When your daughter dies of drugs people like to blame the parents and the child and there was a guy selling poison to kids. That’s the guy who should be held accountable,” said Cliff Golden.

The effort to convict Layton began in 2018 when ousted State Attorney Andrew Warren decided to prosecute under a seldom used law that allowed prosecutors to go after Layton for selling a deadly dose of drugs.

Warren expressed his feelings on the conviction Monday: “For five years, people in the system said we shouldn’t bother going after those responsible for Katie’s death. I made it my mission to deliver justice, and I knew all that fighting was worth it when I spoke with Katie’s family after the conviction was finalized last week.”

Cliff Golden says the conviction is justice for Katie.

“I was always told it was a hard case to prove but when we got to the end, they have put two bad guys in jail for the death of my daughter, so we are pleased,” said Golden.