Cassandra Rhines never made it to her goddaughter's birthday party in Minneapolis. Nearly three decades later, authorities say that they now believe she was murdered and her body was left in an isolated part of a state park on Lake Superior.

With the help of modern-day DNA analysis and samples provided by Rhines' family, scientists with the Minnesota Bureau of Criminal Apprehension (BCA) announced Wednesday that they identified her skeletal remains and are launching a homicide investigation.

"We're looking for any information about her disappearance, and who she may have been with, who she had contact with, who her friends may have been because we just don't know a lot about her and her life at that time," BCA Assistant Superintendent Drew Evans said at a news conference.

Rhines' remains were found in Gooseberry Falls State Park last May by an off-duty Lake County Sheriff's Office employee, said Lake County Sheriff Carey Johnson.

Her skull appeared to have been damaged, leading authorities to believe Rhines was murdered, Johnson said.

Rhines was 19 years old when she went missing in June 1985. She was last heard from when she called a friend to confirm that she would go to her goddaughter's party in Minneapolis. Rhines lived in an apartment complex at 2700 Grand Ave. S., near Whittier Park, in Minneapolis.

Authorities said they want to hear from anyone who lived in the area at the time and who may have information helpful to the investigation.

Investigators believe Rhines may have been involved in prostitution and may have worked as an exotic dancer. They also believe that she may have been living with a man and are seeking help to identify him.

BCA scientists were able to obtain a full genetic profile from the remains and enter the information into a national missing persons DNA database. Rhines' DNA was matched to that of a family member who provided DNA to the BCA in 2013, and another family member which provided DNA for further testing.

"One family's decision to come forward was key to the successful identification of these skeletal remains," said BCA forensic science services director Catherine Knutson.

The BCA has campaigned for family members of long-missing Minnesotans to step forward so that investigators can conduct DNA comparisons. Forensic scientists first started using DNA to test remains around the year 2000, but in the past few years, DNA extraction and testing capabilities have become more sensitive so that scientists can derive DNA from old remains even if they are in poor condition.

"The forensic technology gets us to the starting point in this case," Evans said, but he added that the public's help is what could help solve the case.

Anyone with information about Rhines is asked to contact the Lake County Sheriff's Office at 218-834-8385 or the BCA at 651-793-7000 or via email at bca.coldcase@state.mn.us.