Officers said a 43-year-old man arrested in connection with the "tragic and horrific" sustained attack has been bailed pending further inquiries.
Floral tributes have been left at the scene in Boundary Avenue, with one displaying the message "RIP Nan".
Tests are being undertaken to establish the breeds of the dogs.
The property remained sealed off today following the incident on Friday, and a large police van was parked outside the house.
Speaking at a press conference outside West Bromwich Police Station today, Superintendent Phil Asquith said: "Neighbours called to report that a woman, 85 years of age, was under attack from dogs from a neighbouring property.
"Our officers attended, by which point the dogs had returned through a hole in the fence to the adjacent property and then, unfortunately, despite the best efforts of medical professionals, that lady died at the scene.
"An operation was then undertaken to secure the dogs. They were tranquilised and transported subsequently to secure kennels where they currently remain.
Watch the police press conference:
"They are being tested to determine their breed and specialist officers are now working with the family to offer them their support at what is a tragic and horrific incident.
"Fortunately, these types of incidents are rare. This presented no wider threat to the public. It was a hole in adjacent premises so they weren't running in the streets.
"It was contained and the male who owned those dogs was arrested yesterday. He has subsequently been bailed for further inquiries whilst we undertake a forensic post-mortem to determine the cause of death and to determine the breed of the dogs involved."
Armed police, paramedics and an air ambulance were sent to the scene at around 3.20pm on Good Friday but the woman could not be saved.
Neighbours said the dogs appeared to be pit bulls, however this has not been confirmed.
Asked what injuries the victim had suffered in the incident, Superintendent Asquith said: “The dogs will have unfortunately carried out a fairly sustained attack so there were multiple injuries, mainly caused as a result of the delay in getting into the garden.
“But the specifics of the injuries I can’t go into.”
Speaking about the breed of the dogs, Superintendent Asquith said: “They were two large dogs but we cannot speculate.
“The DNA samples have to be taken to determine the specific breed under the Dangerous Dogs Act (to see if) they are specific breeds that are banned – and I can’t speculate as to whether or not they are banned dogs.”
Superintendent Asquith said neighbours responded “very quickly” to the pensioner being attacked and family members were able to access the garden quickly as they lived nearby.
He added: “Fortunately, the actual owner returned home and was able to get the dogs back into their area at the adjacent premises.”