A body buried in an unmarked grave has been identified through DNA evidence as that of a 15-year-old Hobart girl who vanished in 1980, police said.

Detectives were investigating the death of Paula Ann Stewart as a homicide, said Lake County Sheriff Roy Dominguez.

"We have suspects but need the public's assistance," Dominguez said Monday.

The Lake County coroner's office declined to discuss the cause of her death.

The body was buried in a cemetery operated by the Ross Township trustee's office in Merrillville, Domiguez said. Trustee John Rooda said the skeletal remains were discovered by police almost six months after Stewart's reported disappearance in June 1980. Authorities delayed burying the body until 1984 as investigators worked to identify the remains, police said.

The case was reopened in late 2006 after Stewart's sister contacted Hobart police asking about the investigation.

The sheriff's office and Hobart police arranged to exhume the remains earlier this summer.

The Lake County Coroner's office and Stephen P. Nawrocki, a biology and anthropology professor at the University of Indianapolis, positively identified the body.

"We were pleased to be able to assist the local authorities with this case," Nawrocki wrote in a statement. "We are very glad that Paula has finally been identified after all these years."