NEWARK, N.J. (AP) _ A woman identified as one of two people who died in a fire earlier this week is alive, but the mistake was not discovered until she regained consciousness after two days and started muttering her name, her son said.

Mary Underwood, 66, was in critical condition at St. Barnabas Medical Center after suffering severe burns in the fire that killed her husband, Paul, and another woman.

''Apparently, she initially began to mouth the name Mary,'' said Arthur Underwood, the woman's son. ''They thought she was asking how Mary was and not that she was Mary.''

When an autopsy of the other woman revealed other discrepancies, authorities realized a mistake had been made, said Underwood.

The second victim was Nancy Kniep, said Sgt. Jack Dempsey of the Morris County prosecutor's office.

The Underwods, who lived in Columbus, Ohio, were staying at the Randolph Township home of Mrs. Kniep and her husband, Louis, when the fire broke out, said Underwood.

Kniep, who escaped without injuries, initially identified the severely burned female body as that of Mrs. Underwood, Underwood said.

''He was in shock,'' said Underwood. ''Then everything just went forward on the basis of that (identification). We were advised that my mother was killed.''

Underwood said police came to his home Wednesday to tell him that his mother was alive.

''They said there's been an error,'' he said. ''I'm happy that she has a chance. It's still very much in the air whether she'll actually make it.''

He said he went to the hospital after hearing the news, adding that his mother was conscious but barely able to speak because she was hooked up to a respirator.

Underwood said his parents formerly lived in New Jersey and met the Knieps some 30 years ago. His mother once worked for Kniep's graphic arts business, he said.

Paul Underwood, 70, was a correspondent for The Associated Press and The New York Times before becoming a professor of journalism at Ohio State University.

Underwood said his parents' home in Columbus was burglarized Tuesday after the address was printed in an obituary in a local newspaper.