An Ivy League economics professor, who coolly carried a drink in one hand and his dead wife's coffin in the other, denied Thursday that he had anything to do with her murder.

Ellen Robb, 49, was found brutally beaten to death on Dec. 22 in the Pennsylvania home she shared with her husband, University of Pennsylvania Prof. Rafael Robb, 56. Police believe the murder was staged to look like a robbery.

"The person that attacked Mrs. Robb was trying to depersonalize, wipe her face off the map, and in fact he did that," said Montgomery County District Attorney Bruce Castor.

"That doesn’t sound like any burglar to me, that sounds like Mrs. Robb was specific object of the attack."

Her husband raised eyebrows when he appeared Tuesday as a pallbearer at his wife's funeral, dressed somewhat informally, wearing a cap, and toting a drink in his free hand as he helped carry his wife's casket.

Forensics psychologists concluded Ellen Robb was beaten with a force much greater than necessary to kill her, something police have never seen in a burglary case.

Castor added circumstantial evidence "very strongly" indicates that her husband had a role in the killing.

"He has both motive and opportunity, and I think right now he has a great deal of explaining to do," Castor said.

Mrs. Robb was in the process of filing for divorce from her husband at the time of her death, a fact investigators believe may be a motive in her murder.

When asked point-blank whether he killed his wife, Robb told FOX News' Rick Leventhal, "I did not kill her."

Castor said Mrs. Robb told several people that she had hired a divorce attorney and planned to move into her own townhouse on Jan. 1, Castor said. She also reportedly said she believed her husband had money hidden in overseas accounts.

Robb's attorney, Francis Genovese, didn't immediately return messages left at his office Wednesday afternoon. Genovese told KYW-TV in Philadelphia that his client was cooperating with investigators.

Prosecutors took DNA samples and fingerprints from Robb to compare them with evidence discovered after his wife's body was found in the kitchen of their house in upscale Upper Merion Township, just outside Philadelphia. A murder weapon has not been found.

The professor told investigators that he last saw his wife alive before driving to work on the morning of her death. He called police later that afternoon to say he had found her body when he returned home, but authorities are questioning why he didn't call 911 immediately after finding his wife's body.

When asked by 911 operators how he knew his wife was dead, Robb reportedly said, "Her head is cracked."

Robb, who is originally from Israel, has taught at the university for more than four years, according to a resume posted on the school's Web site. Robb reportedly was not scheduled to teach any classes during the upcoming semester.

The Associated Press contributed to this report.