A case typically begins with a judge or court commissioner ruling whether, based on the evidence, there is probable cause to believe a crime has occurred, and the defendant should be held in detention while the case proceeds. But the Justice Department reported that St. Louis County Family Court barely considers the evidence for probable cause, and juveniles are illegally denied the chance to challenge that evidence. The same holds true, the report said, for rulings on whether to transfer a case to adult court.

The poorest defendants in Missouri are represented by a state-funded public defender. In other courts around the state, the Justice Department found, the public defender’s office decides whether a person is poor enough to qualify for that free representation; in St. Louis County Family Court, the decision is made by the judge or court commissioner, and different ones use different standards.

People who are not as poor but still cannot afford a lawyer are assigned to one of a handful of private-practice lawyers, but typically not until the defendant has already been in detention for a week or more, and sometimes for months.

Reviewing a selection of cases handled by the public defender, the Justice Department found that the lawyer never challenged a probable cause finding, hired an expert witness or appealed a judge’s finding. The lawyer rarely asked for a mental health examination of the juvenile, moved to dismiss charges or challenged hearsay evidence or leading questions. Out of 277 public defender cases resolved last year, just three had the equivalent of a trial; most ended with the minor admitting guilt.

Another trouble spot, the report found, was the conduct of hearings where juveniles gave the equivalent of guilty pleas, with court officials often reciting complicated statutory language about the alleged transgressions, then leading the children through what the report characterized as “formulaic ‘do you understand?’ and yes/no questions.” The report said judges made no real effort to determine whether pleas were coerced, whether defendants had any criminal intent, or whether they understood the full consequences of admitting guilt.

Citing a transcript from one hearing, the report said: “Despite the child’s dutiful ‘Yes, sir’ replies, there is no indication in this transcript that she has legal capacity, comprehends the rights she is waiving, is admitting to facts that satisfy the elements of the statute she is charged with violating, or understands the language of that statute.”

The St. Louis County investigation, which began in November, 2013, is one of four the Civil Rights Division has begun into juvenile justice systems.

An investigation into Shelby County, Tenn., which includes Memphis, found similar problems to those documented in St. Louis County, and officials there agreed in 2012 to make changes. The department filed suit over juvenile justice conditions in Lauderdale County, Miss., and reached a settlement this year with the state and the City of Meridian, but the case against the county continues. An investigation into Dallas County, Texas, has just gotten underway.