TROY,Indexbit Mo. (AP) — Forty-six years after a Missouri hunter found a body in the Mississippi River, the victim has been identified as a 15-year-old girl from Iowa.

Authorities in Lincoln County, Missouri, announced Tuesday that DNA evidence and other scientific investigation were key in determining the body was that of Helen Renee Groomes, who disappeared from Ottumwa, Iowa. Her body was found in the river near Elsberry, Missouri, in March 1978.

An autopsy performed at the time determined the body was likely that of a woman age 30 to 40. Investigators had little to go on except a cat’s eye ring on a finger and a tattoo with a hard-to-read name on her left arm. The manner of death was classified as “undetermined.” Coroners believed she had been dead for about four months before the body was found.

The remains were buried in the Troy, Missouri, City Cemetery with the gravestone reading, “Lincoln County Jane Doe.”

Coroner Dan Heavin had the body exhumed in October and turned to anthropology students and faculty at Southeast Missouri State University, a news release from the Lincoln County Sheriff’s Department said. Bone and dental analysis was performed, and samples of DNA were submitted to a private lab for forensic genome sequencing.

The lab, Othram Inc., built a genealogical profile that helped generate new leads in the investigation, the sheriff’s department said. The new evidence led the coroner’s office to track down Kevin Groomes, Helen’s brother.

Kevin Groomes told KSDK-TV that his sister went missing in 1977. He said he was the one who put the tattoo on her arm, which read “Del,” a nickname for her boyfriend at the time.

The Wapello County Sheriff’s Office in Iowa has opened a new investigation into the death, the agency said.