LEWISTON — Human remains found inside a freezer that was tucked away for years in a storage unit were those of a former girlfriend of the man who rented the unit, law enforcement officials said today.

Because of decomposition, tissue samples from the body had to be sent to a Pennsylvania laboratory, which used DNA from the remains and a DNA sample from a relative to confirm the identity of Kitty Wardwell, said Steve McCausland, spokesman for the Maine Department of Public Safety.

The state Medical Examiner’s Office determined that Wardwell’s death was a homicide, but the cause of her death was being withheld today.

“We’re in the initial stages of this investigation. At this point, withholding the cause of death is appropriate as we try to get further answers,” McCausland said.

The storage unit was rented by Wardwell’s former boyfriend Frank Julian, who died Oct. 1 at age 80. Wardwell had been missing for 28 years.

The body was discovered by family members cleaning out the 10-by-10 storage unit, which the storage company owner said Julian paid for in advance every three months. The body was inside an unplugged freezer, a floor model with a door that opened on the top.

There is a nine-year gap in between the time that Wardwell disappeared and the time Julian rented the locker, so investigators have many questions to answer, including where she died and where her body was before being placed in the storage unit, officials said.