Three lawyers and a private investigator are suing D.C. Superior Court, arguing that the court is violating federal law by failing to pay them promptly for representing indigent criminal defendants in the District.

The lawsuit, filed late last week, contends that the District's primary local court sometimes does not pay its bills for months. The lawyers challenge a legal interpretation made by Chief Judge Eugene N. Hamilton defining when payment is due.

Coming during a stretch when federal auditors said Superior Court failed to monitor its money flow and a U.S. District judge complained about the court's failure to make essential documents available in a class-action case, the lawsuit renews questions about courthouse management.

Congress, angered by Superior Court's 1998 decision to delay payment to hundreds of attorneys for poor D.C. residents, ordered the court to follow a federal law that requires payment within 30 days of receipt of a bill. If the court missed the deadline, it was required to pay interest and penalties.

Lawyers Steven G. Polin and Gary M. Sidell contend that the court repeatedly flouted the law during this budget year and last by paying slowly and by refusing to pay interest. A central part of their claim concerns how Hamilton has ordered the cataloguing of bills.

A lawyer appointed at $50 an hour to represent an indigent criminal defendant, a neglected child or an incompetent elderly citizen submits an invoice to the court's finance office. The judge presiding over the case evaluates the bill, perhaps adjusts it, signs it and forwards it for payment. The process sometimes takes weeks. Sometimes, lawyers report, it takes months.

With the federal Prompt Payment Act newly in force, Hamilton informed judges in December 1998 that the court would be liable for interest if a "proper invoice" were not paid within 30 days. Crucially, he said the clock would not start ticking when the court officially received the bill, but only once a judge had approved payment.

Polin and Sidell, joined by lawyer Betty Ballester and investigator Steven Roth, cried foul. Polin said yesterday that Hamilton's policy "stands common sense on its head."

"We work hard. We represent our clients diligently. We've got financial obligations, families to support. We've got bills to pay," Polin said. "The attorneys and investigators shouldn't be made to suffer because of whatever problems the courts are having."

General Accounting Office auditors delivered a report in October sharply critical of Superior Court's financial management structure and practices. As of July, for example, the child support account had not been reconciled in 14 months. An audit of courthouse personnel practices is still in progress.

A search is underway to fill two of the court's more important jobs. The court's fiscal officer, John F. Schultheis, retired abruptly in July as financial auditors completed their work. Under fire, Court Executive Ulysses B. Hammond announced his own resignation, effective Feb. 18.

Hamilton, who is due to complete a second four-year term as chief judge in 2001, also had a rough year. At one point, his four colleagues on the court's governing committee concluded he had overstepped his authority in ordering administrative changes for the court. A federal judge criticized him in August for failing to deliver Superior Court records needed to improve the care of retarded residents of D.C. group homes.