It was a three-ring circus day yesterday in the Manhattan Criminal Court building at 100 Centre St.

At its best, the criminal justice system is a great leveler – bringing down the high and mighty as well as the poor and powerless.

At its worst, it is a system that can be unjust, manipulated, and corrupted.

Yesterday, on various floors and in various courtrooms, it had the makings of all of the above in cases big and small, from prostitution to corporate theft to murder. It even had a celebrity of sorts.

Ring One: It began at about midnight, in one of the arraignment parts on the ground floor of the mammoth courthouse, when Rudy Fleming, the accused killer of actress Nicole duFresne, was brought in to be arraigned on murder charges.

Wearing a gray sweatshirt and baggy pants, Fleming, a 19-year-old ex-convict accused of shooting duFresne in a botched mugging, appeared to be sleeping as prosecutors outlined their case.

Judge Anthony Ferrara ordered he be held without bail – remanded, in court speak. Hours later, a friend of Fleming’s, David Simmon, was arraigned in the same room on a related robbery charge.

The arraignment part is the entry level of the criminal justice system. The courtroom is well-worn and seems older than its years. Water stains stretch across the ceiling in AP2 and the benches are pockmarked and imbedded with deep scratches. The walls are bare except for a jumble of wires in a corner of the room usually packed with black and brown faces.

Assembly-line justice is dispensed here. In one half-hour period, Judge Karen Lupuloff disposed of 10 cases ranging from disorderly conduct to identity theft and grand larceny; the defendants were ages 19 to 67; at least one was HIV positive.

Each case began with a court officer reading the docket number and ordering the defendant to step up. An assistant district attorney quickly sorted through the paperwork while defense lawyers, mostly from legal aid, tried to keep up. The cases usually ended with the officer admonishing the defendant to appear when next required “or a bench warrant will be issued for your arrest.”

Ring Two: The trial in progress 12 stories above, in courtroom 1324, provided a stark contrast. In that comparatively immaculate, high-ceilinged courtroom, the second trial of a former Tyco chairman, Dennis Kozlowski, was in its second day.

Instead of one overworked prosecutor and a small team of public lawyers, there were three prosecutors and a collection of tanned, well-coifed, highly paid defense attorneys. The benches were generally unmarked and the faces – in the well and the audience – were almost all white.

Rather than a case involving street thugs accused of mugging – or killing – someone for a few dollars, Mr. Kozlowski and his former chief financial officer are accused of stealing $150 million from their company and using it to throw lavish parties and buy cars, planes, and a $6,000 shower curtain.

The walls were covered with display screens and the benches were packed with business writers and the tanned and well-dressed relatives of the accused corporate crooks, whose proceeding ended in a mistrial.

Ring Three: A few floors down, lawyers for Knicks legend Bernard King worked out a deal on his latest brush with the law. The 47-year-old former basketball star, who once scored 60 points in a game, was charged with beating up his wife.

She filed the original complaint but has stopped cooperating with police. The glowering King, who was charged with sexual abuse in 1986 and domestic abuse in 1994, agreed to attend 10 marriage-counseling classes in return for the charges being dropped.

Back to Ring One: Then it was back down to AP2,where accused “East Side Madam” Julie Moya was arraigned on charges of running a call-girl ring that used at least one 15-year-old and grossed up to $6 million a year.

Prosecutors say Moya, who also has been dubbed the “Menagerie Madam” for her collection of 25 exotic pets, oversaw two dozen women who earned up to $600 an hour for sex.

Prosecutor Matthew Bassiur said Moya, who looked disheveled in a lumpy gray sweater, tight jeans, and stiletto heels, did time in federal prison for selling drugs and should be held on $2 million bail.

Defense lawyer Daniel Ollen called that figure “ridiculously high” and said the police had better things to do than bust madams. Judge Lupuloff set bail at $500,000 and Moya click-clacked back to jail in her high heels.

All in all, another day’s worth of justice at 100 Centre St., sometimes fast and sure; often slow, uneven, and incomplete – but always worth the price of admission.