On December 22, 2006, someone brutally murdered Ellen Robb, age 49, of Upper Merion Township, just outside Philadelphia, Pennsylvania.
Around 1:45 that day her husband called police to report the crime. He said he’d found Ellen dead upon returning from work. Rafael Robb, 56, also stated he last saw Ellen alive as he left for work that morning.
Work for Rafael Robb is teaching Game Theory, Industrial Organization, Law and Economics, and Public Economies at the University of Pennsylvania.
For some reason, Rafael Robb’s last name lost a “b” on the UPenn website. This may not make sense, but it does make it easy to differentiate between information about the murder of Ellen Robb and posts online about the professor relevant to his job.
Professor Robb was suspected immediately in his wife’s murder. The police took property, including personal computers, and Bruce Castor, District Attorney for Montgomery County, PA, has stated that Robb cannot be excluded as a suspect.
The Montgomery County D.A. issued a press release about the crime on December 23rd. It read, in part:
… On December 22, 2006, Forensic Pathologist Dr. Ian Hood conducted an autopsy and found that Ellen Robb was struck repeatedly with a long, solid, cylindrical shaped object. This weapon has not been recovered. He also found defensive wounds showing that she tried to fight her attacker. He ruled the cause of death as multiple blunt force trauma and the manner of death homicide.
Investigators are searching for this murder weapon, along with bloodied clothing and footwear they expect the killer discarded. If anyone has information about the killing or any items of potential evidentiary value, please contact Upper Merion Police at (610) 265-3232 or Montgomery County Detectives (610) 278-3368.
Authorities investigating Ellen Robb’s murder have also stated that it was a singularly bloody, gruesome crime, and that the person who bludgeoned Ellen Robb to death staged the scene to look like a burglary.
It became obvious as to what Ellen’s family thought at her funeral. From the Philadelphia Daily News, an article published December 30, 2006:
GAZING at his sister’s coffin, Gary Gregory could barely contain his grief.
“She was an angel on earth,” he said of Ellen Robb, choking back a sob. “She was too good to keep here.”
As the tear-streaked faces of those packed in the tiny Montgomery County church nodded in emphatic agreement - remembering the stay-at-home mother for her warmth, generosity and dedication to her 12-year-old daughter, Olivia - one spectator sat conspicuously still.
Rafael Robb, listening stoically from the front row, had also just given a eulogy to the 150 people in the sanctuary of the Radnor United Methodist Church. But his delivery had elicited discreet, disapproving head-shakes and even a few scoffs and unintelligible mutterings.
A week after Ellen Robb was found murdered in the couple’s Wayne home, it was clear that some of the mourners at the funeral yesterday wondered whether her balding, bespectacled husband - a University of Pennsylvania economics professor - had played a role in her still-unsolved slaying…
An abstract from a paper by Rafael Robb and Huanxing Yang was published online earlier this year. The paper delved into Game Theory, and was titled “Long-Term Relationships as Safeguards.”
Applied mathematics and economics overlap in Game Theory. It is a branch of both where study is focused on how different choices made by players affect, and hopefully increase their returns. The following is from the paper by Professor Robb and Huanxing Yang:
Players are also able to strategically choose whether to continue interacting with the same partner - form a long term relationship - or separate and seek a new partner. We show that the ability to form long term relationships facilitates the achievement of cooperative outcomes without information flows, without instability due to observational errors, and without a central coordinating device to synchronize players’ actions. We also show that the heterogeneity of types helps, rather than hinders, cooperative behavior by inducing players to avoid bad types that inflict low payoffs on them and seek good (or opportunistic) types that bestow high payoffs…
The paper sought to demonstrate (it goes on to further illustrate its point with equations unintelligible to the layperson) that in a certain kind of structured game play, long-term relationships between players were a wiser choice that safeguarded the players’ ability to win.
In many news articles published since Ellen Robb was murdered, one strange element of her relationship with her husband has become clear: the Robbs had been living estranged in the same household for nearly a decade. Married, but separate lives, linked only by their daughter, Olivia, age 12.
Only recently had Ellen Robb finally decided to file for divorce.
I think some will tell you that marriage is a game. Two partners playing against life, and sometimes each other.
If Professor Rob(b) murdered his wife, was it because she’d finally decided she no longer wished to be part of the equation? For years they’d maintained a basic partnership, no more, living that odd existence some couples choose, where they become more like roommates than anything else.
What happened in the Professor’s cool and mathematical mind when his wife Ellen finally told him it was time for her to opt out of this particular kind of “game play?”
There is an ongoing discussion about this case at Websleuths.com. I’ll post more entries here as they are warranted. Finally, here is a short list of links related to Rafael Rob(b):
- Rob(b)’s webpage with the University of Pennsylvania;
- Dr. Robb’s full curriculum vitae;
- Abstract of a paper Robb wrote with Joel Waldfogel — “Piracy on the Silver Screen.”
UPDATE, 11:28 p.m. ET
This insight was achieved in part after I received an e-mail from fellow crime blogger LiLO, webmistress of Lost in Lima, Ohio, a true crime blog.
This online paper; “Gun ownership is not the cause of America’s high murder rate,” is basically a pro-gun ownership argument, but within the paper was inserted the following paragraph — a statement I found relevant to the story of Rafael and Ellen Robb:
A central tenet of game theory is that attackers have the advantage over defenders. A defender must defend against all possibilities of attack, and in doing so defends none of them very well. An attacker has to choose only one line of attack, and therefore can do it extremely well. Attackers have the advantage of surprise, planning and initiative. An example is a careful, well-considered plan to shoot someone in the back, even if the person is openly carrying a sidearm…
LiLO pointed me to this article: “DA: Still analyzing Robb murder.” The following quote is from the piece, published December 29 in the Times Herald:
With no arrest, additional intrigue swirls around the case. Questions at the press conference ranged from Dr. Robb being a flight risk because he was born in Israel to possible attempts to apply what is known as the concept of Game Theory.
According to what Castor has been able to glean, Game Theory is an economic philosophy wherein a person can apply factual scenarios for a desired outcome.
“In a criminal context, somebody applying it would calculate all the angles and then go ahead and commit the crime,” said Castor. “It could also be a coincidence, too (that Robb taught classes on Game Theory).”
An interesting possibility as to who murdered Ellen Robb was also mentioned in the same article:
[DA Castor] also admitted that investigators were initially looking into the angle of a murder-for-hire scheme, as was the case with the Rabbi Fred Neulander murder, but that the investigation has since taken a different course.
“Early on, we considered it,” he said. “We do think it’s possible but, right now, we are leaning away from it.
“The best way for two people to keep a secret is for one to be dead. Rabbi Neulander is in prison.”
This quote was doubly intriguing following the mention of Game Theory. DA Castor was applying some Game Theory of his own. The idea of the killer of Ellen Robb being in cahoots with another would have been rejected by a man with intimate knowledge of The Prisoner’s Dilemma. From the Wikibooks Introduction to Game Theory:
Two men, [X and Y], were arrested after an armed robbery. The police had enough evidence to convict the two for the theft of the get-away car, but not enough to convict them for the actual armed robbery. However, if the police could get a confession from either of the two men they could conceivably convict them both for the armed robbery…
The men are given a set of choices by police: If X confessed and Y did not, X would be freed and Y charged witht he crime and given 10 years in prison — the reverse would be true if Y confessed; X and Y both confessing would net both men 7 years in jail; Neither man confessing would net them both 2 years for lesser charges.
The prisoners can’t communicate, and they are left alone to make their choices.
According to the Wikibooks chapter, the solution is always both X and Y giving confessions and receiving 7 years.
Dr. Robb would have had a more intimate knowledge of this dilemma than any common criminal.
So, if he did have anything to do with his wife’s murder, he did it alone.





