Often after a heinous murder or a police shooting in Philadelphia, the suspect is found to have a lengthy criminal record or an outstanding warrant for another crime. That prompts many to ask: "Why wasn't this creep in jail?"

A four-part series that begins in The Inquirer today answers that question. It details a criminal justice system practically built to perpetuate crime, rather than stop it. Thugs go on committing crimes until they escalate into murder.

Police may do a good job of capturing suspects, but after that comes the revolving door. Various breakdowns in the legal system enable thousands of suspects to go free.

The city's inability to lock up criminals emboldens repeat offenders and increases violence.

Among the nation's 10 largest cities, Philadelphia has the highest rates of homicide, rape, robbery, and aggravated assault - plus one of the worst conviction rates.

A review of 31,000 cases filed from 2006 to 2008 found that only about 20 percent of the violent crimes ended in felony convictions. The violent-crime conviction rate in other big cities is about 50 percent.

District Attorney Lynne M. Abraham disputes The Inquirer's findings regarding the low conviction rate compared with that in other cities. However, Abraham - who has been the DA for 18 years - has failed to keep her own records that could benchmark the office's results.

The court system appears overwhelmed and disjointed.

Judges are under pressure to move cases. Meanwhile, defense lawyers look for delays. Prosecutors scramble to coax witnesses who are being threatened. A broken bail system enables defendants to skip trials with impunity.

All this leads to cases getting dropped or dismissed.

Philadelphia's Municipal Court gives prosecutors three chances to conduct a preliminary hearing to move the case forward. After "three strikes," the case is thrown out, and the suspect goes free.

Defense attorneys know this and try to game the system. Other systemic problems clog the system and force cases to get dropped as well.

While there's plenty of blame to go around, much of the problem seems to stem from a dysfunctional Clerk of Quarter Sessions and an overworked, disorganized District Attorney's Office.

Clerk of Quarter Sessions Vivian T. Miller oversees a broken bail system. There are almost 50,000 fugitives in the city. Defendants who have skipped bail owe the city $1 billion. There seems to be no effort to fix the problem.

Other case management issues doom cases as well. Multiple court delays frustrate witnesses who eventually give up. Police are often booked to appear in two different courtrooms at the same time.

An overhaul of the court system isn't easy, since there are so many disconnected parts. But much of the burden for leading the reform could come from the DA's office.

It's good for the city that Abraham did not run for reelection and will leave office next month. It will be up to incoming DA Seth Williams to bring real change.

A fresh approach to managing and tracking cases could boost convictions and reduce the number of cases that get dismissed. But broader reforms are also needed to fix a broken system.