Gallery owner Bonnie Lindberg said she had been told she would probably never see the paintings again, reports Correspondent Robin Taylor of CBS station KYW-TV.
But two of the paintings surfaced in April and on Thursday, the FBI announced the recovery of two more works, worth a total of $175,000. Negotiations are under way for the return of the remaining three.
Lindberg said the three remaining paintings, valued at more than $700,000, were found at the same Rio de Janeiro art dealer where the first two were recovered in April.
FBI officials could not confirm that, but said the three paintings are believed to be in South America.
The two paintings just recovered are She's My Baby and Lickin' Good Bath.
Valued at $40,000, She's My Baby appeared on the cover of the June 4, 1927 issue of The Saturday Evening Post and depicts a boy painting a heart on the back of a girl's coat. Lickin' Good Bath is worth $135,000 and was used in a calendar designed by Brown & Bigelow. It shows a dog licking the face of a boy who is bathing.
The paintings will be returned to their respective owners, a private collector and the Minnesota-based Brown & Bigelow company, the FBI said.
Exactly where they have been remains a mystery. The stolen art work turned up in a gallery in Center City when a man from Brazil asked to have the paintings appraised.
Â"We found out they had been stolen,Â" said art dealer George Turak. Â"Four or five days layer, I called him.Â"
Turak told the man he would have to notify the FBI. The Brazilian man was given the paintings several years ago as payment on a loan and apparently had no idea they were stolen.