UPDATED 08/11/11 7:42 a.m.

LISLE, Ill. (CBS) — A Naperville dentist, allegedly behind the wheel of a luxury sports car that went the wrong way down the Ronald Reagan Memorial Tollway and killed two people, was already known in the DuPage County court system.

As WBBM Newsradio’s Michele Fiore explains, William Howe, 43, was arrested for allegedly driving under the influence in Naperville in February. But, prosecutors say he didn’t show up to court.

LISTEN: WBBM Newsradio’s Michele Fiore reports

While that case is pending, law enforcement sources say this past weekend, Howe took a 2006 convertible Porsche into the turnaround lanes of the Reagan Tollway near Lisle and crossed into the oncoming lanes, killing Farnaza Ali, 37, and her 74-year-old father, Sherali Shalwani of Elmhurst.

Howe himself was left in critical condition, police say.

Illinois State Police won’t confirm Howe was the driver, but will confirm witness reports of cash flying out of the little red car as it drove eastbound on the Tollway near Lisle, used a turnaround to cross into westbound lanes, and still traveling east collided head-on with a Toyota Corolla carrying an Elmhurst family on their way to a prayer service.

Howe’s Naperville home is in foreclosure, underwater by $100,000, and his dental practice — Dr. William A. Howe, DDS in Aurora — is closed.

The 43-year-old qualified for a public defender in his pending case of driving under the influence of drugs.

Howe told a DuPage County judge when applying for a public defender to represent him in a DUI case from earlier this year that his only income was $1,100 a month in disability. He cited assets of his home, whose mortgage exceeded its value by about $100,000, and a 2000 Jeep. He did not mention the 2006 Porsche, which the secretary of state said is registered to him at his home address.

A neighbor said Wednesday the house has been on and off the real estate market for several years. She said several police cars were parked outside Monday.

No one answered the door Wednesday morning. The blinds were closed and the porch light was on, and a note on the garage door of the two-story home told “Bill” that a neighbor would take care of mowing his lawn — but a lawn service arrived later to cut the grass.

A dentist in Illinois since 1993, Howe ran his own practice in Aurora until 1 1/2 years ago. His dental license is valid and current, according to the state department of professional and financial regulation, and he has no history of professional discipline, a spokeswoman said.

He filed for bankruptcy in 2002, citing corporate debt. He bounced a check in 2010 to pay a traffic fine for expired plates out of Beecher, where Howe has relatives, forcing Will County officials to seek $143 from him using a collections agency.

Howe’s driver’s license also is valid, though a secretary of state spokeswoman said he was convicted in DuPage County in 2010 for carrying open alcohol in his vehicle.

He was arrested in Naperville in 2008 for driving under the influence of drugs, having expired plates, failing to signal and passing in a no-passing zone, but the first three charges were dropped.

And six months ago, shortly before 11:30 a.m. Feb. 6, Howe was pulled over in Naperville near Aurora and Ogden avenues and arrested again for driving under the influence of drugs, having expired plates and failing to signal when changing lanes, court records show.

His bail was set at $3,000 but raised in June after he didn’t show up to court in April; He’s expected back in DuPage County court on that matter in a few weeks.

The Sun-Times Media Wire contributed to this report.

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