The crime seemed both audacious and foolish.

A robber approached a man stopped along the Ohio Turnpike, took his money, then shot him in the face.

The victim, a millionaire physician from Mercer County named Gulam Moonda, died in front of his wife and mother-in-law. After shooting Moonda, the assailant elected not to harm either witness. Instead he fled in a dark van. Both women said they were so terrified they did not notice the license plate, and his wife said she couldn't describe the shooter.

Violent crime is almost unheard of on the 241-mile highway that traverses Ohio. In all of last year, one unarmed robbery occurred on the roadway, and one armed robber held up a store in a service plaza.

So it's not surprising that almost immediately after Moonda's death more than two weeks ago, on Friday the 13th, the highway patrol began wrestling with the case's central question: Was he a random victim of a cruel robber, or a specific target of someone bent on murder?

Police began digging into the backgrounds of Moonda, 69, and his wife, Donna, 46, to determine if someone had a grudge against him. Investigators' tactics upset her so much that she hired a prominent Cleveland defense attorney after being questioned for a second time.

The lawyer, Niki Schwartz, said Donna Moonda has been labeled a suspect by investigators, who think she could have arranged her husband's slaying.

Through Schwartz, she said she is innocent and will continue to help investigators solve the mystery of her husband's killing.

The Moondas' May-December romance began during the 1980s. An immigrant from India, Gulam Moonda became a board-certified urologist and was on staff at Sharon Regional Health Center for 35 years.

Donna Smouse Moonda, a blonde who possessed cover girl looks, graduated from Hickory High School in Mercer County in 1977. She became a registered nurse five years later, a job that produced an introduction to Moonda.

The couple married in December 1990 after signing a prenuptial agreement that would limit her financial claims if they ever divorced.

They lived in a Sharpsville mansion ringed by manicured lawns and mature trees. While keeping a low profile, he amassed millions of dollars and built a sterling professional and civic reputation.

In February 2000, Moonda and a colleague, Dr. Peter Daloni, were featured in a Youngstown, Ohio-based Business Journal article about treating prostate cancer by freezing the prostate and surrounding cancerous tissue.

"That goes to show that this guy was almost on the cutting edge in his practice," said Dr. Jitendra Desai, immediate past president of the Pennsylvania Medical Society and a urologist at UPMC Passavant and Aliquippa hospitals.

Moonda worshipped at Masjid al-Khair, the mosque housed in a complex that also is home to the Islamic Society of Greater Youngstown. The membership of al-Khair includes numerous professionals and their families from Western Pennsylvania and Ohio's Mahoning Valley.

"People came from Sharon, Hermitage. Some people came from East Liverpool, an hour away,'' said Mustansir Mir, the public relations officer for the mosque and Islamic Society.

Mir is also a professor and director of the Center for Islamic Studies at Youngstown State University. Both positions were created through a $500,000 endowment raised by Moonda and a group of other Muslim benefactors in 1996.

Mir said he believed it was the first university chair in the nation funded by a grass-roots fund-raising campaign.

The gift led to the creation of the Center for Islamic Studies in Youngstown State's Department of Philosophy and Religious Studies.

The Moondas also donated annually to the department's speakers series. Along with other supporters of the program, their individual photographs hang in framed display boxes in the department's office suite.

After Moonda's death, acquaintances said he and his wife had seemed happy. Court records and the police investigation, though, revealed trouble.

Donna Moonda was arrested in October 2003 for stealing the painkiller fentanyl from the hospital in Greenville, Mercer County, where she worked as a nurse anesthetist. She usually smuggled the drug home and used it there.

A first-time offender, she pleaded no contest to the crime in August. She received probation, having already gone through in-patient drug rehabilitation at a Gateway clinic in Beaver County.

There she met Damian R. Bradford, a self-described drug dealer. Police say she began a relationship with him, even though he was half her age.

Bradford, 23, of Center, has been named by the highway patrol as "a person of interest" in Gulam Moonda's killing.

Pennsylvania State Police say Donna Moonda bought Bradford gifts and listed herself as a cohabitant of the apartment where he lived. When she told her husband she was traveling to Beaver County for meetings or counseling related to her addiction, she instead went to see Bradford, police said.

Bloody towels and clothing, six cell phones, and $950 in $50 bills were among the items police seized in a raid of his apartment. Whether any of it can be connected to Moonda's death is a focus of the investigation.

For his part, Bradford said the blood on towels is Donna Moonda's, from when she was menstruating.

The sweatpants and white T-shirt that police are interested in, Bradford said, contain his own blood from a motorcycle accident.

Investigators used a search warrant Thursday to obtain saliva from Donna Moonda. The swabs will be used to determine her DNA profile to see if it matches blood on the towels.

Police used another search warrant to obtain the Moondas' prenuptial agreement, the terms of which have not been disclosed.

In affidavits, police said Donna Moonda wanted to divorce her husband and expected to collect $3 million to $4 million in a settlement. Their primary source was Bradford.

Still unknown is whether the prenuptial agreement would have made a multimillion-dollar settlement possible.

In his will, written in 1992, Gulam Moonda set aside 20 percent of his estate for his wife. Police say that would amount to about $1.2 million. She also would get the mansion.

How much life insurance coverage he had through private companies hasn't been divulged.

Perhaps of even greater interest to police is how a robber zeroed in on the Moondas. Traveling with the couple in their gold Jaguar was Donna Moonda's 74-year-old mother, Dorothy Smouse.

In media interviews soon after the shooting, Donna Moonda told of stopping at a convenience store, where her husband may have attracted attention by flashing a wad of cash. She was driving when they left the store, but pulled off the turnpike about six miles later. The plan, she said, was for her husband to take the wheel there.

Why the switch of drivers was done on the roadside, instead of in the store parking lot, is one of the case's oddities. She stopped the Jaguar about 15 minutes south of Cleveland, or three miles from the next exit, in Strongsville.

There, with plenty of daylight at 6:30 p.m., Donna Moonda told police she stood outside the vehicle and saw the robber attack her husband.

Even so, she could not provide a description of the killer, other than his approximate height and what he was wearing. Those details have not been disclosed by investigators.

For a day or two after Moonda's slaying, turnpike travelers were wary, even fearful. Then motorists began dissecting the crime with questions of their own.

For instance, if Moonda was being tailed by a bandit who spotted him in the convenience store, was the crook prepared to follow him across the state, if necessary, to steal his money?

Police said they consider it strange that the robber turned murderous after getting the money he was after. Odder still is that he left two witnesses who could identify him, said Sgt. Stephanie Norman of the highway patrol.

Like so many of Moonda's friends, Thomas A. Shipka, chairman of the Philosophy and Religious Studies Department at Youngstown State, said he does not know what to think of the details that have emerged about Donna Moonda in court records.

"I hope the police investigation exonerates her,'' he said. "But let the chips fall where they may. Let the police do their job."

Last week, Shipka said, he was so shaken by Moonda's death that he got on his motorcycle and drove the Ohio Turnpike. Stopping at the spot still marked by two red traffic cones, he mourned the loss of the man he respected and brooded over the questions.

"I had to see the site for myself,'' Shipka said. "It's just so strange. Here's this quiet, civic-minded person, who's generous to a fault, dying this way. It's the definition of a tragedy.''