"It really raises a whole level of emotional distress that we didn't anticipate," Gregory said. He said the family was "shocked" and expected Robb to serve more time.
The parole board's decision says Robb was granted parole because of his "participation in and completion of prescribed institutional programs," his "positive institutional behavior," a positive recommendation from the Department of Corrections and his "acceptance of responsibility."
Parole board officials wouldn't confirm the exact date of Robb's release, citing safety concerns.
Robb had previously been interviewed in October 2011, but was denied parole at that time, said Leo Dunn, spokesman for the Pennsylvania Board of Probation and Parole.
Montgomery County District Attorney Risa Vetri Ferman said she recently learned of Robb's scheduled release. She says she's asked the state parole board to reconsider the decision.
Ellen Robb's relatives are also pushing for the board change its mind. They're asking family and community members to write new letters to the board.
"We're hoping than an updated outpouring will serve as new data for the parole board," Gregory said. But, he said, the family is "pragmatic" and recognizes that the board doesn't reconsider decisions often.
Dunn said the board will re-evaluate its decisions if members receive new information about a case. But additional letters that reiterate already-known details won't lead to a review, he said.
The former economics professor applied last year to participate in a pre-release program run by the Pennsylvania Department of Corrections, according to Montgomery County First Assistant District Attorney Kevin Steele.
Police found Ellen Robb in her kitchen beaten beyond recognition with a chin-up bar.
Describing his wife's slaying at a 2008 sentencing hearing, the former professor told a judge he "lost it" when the two began fighting over her holiday vacation plans.