When D.C. police sit down at a station to question a suspect in serious crime, they are required, under almost all circumstances, to record the interrogation on video.

It's the law, and it has been for two years. But for just as long, D.C. police have flouted the statute and the department order that followed it by recording only a small fraction of their interrogations.

So the D.C. Council is looking to raise the stakes, and it is facing opposition from police and prosecutors.

Under a proposed law, if the police do not record an interrogation from the time the Miranda warning is given, the suspect's statements would be presumed to be involuntary and therefore inadmissible in court.

Prosecutors would be allowed to challenge that presumption, but it would be a new burden for the government.

Supporters of the proposal expect that the police, faced with the prospect of losing cases, will quickly become more diligent in recording interrogations. Whatever the strategic advantages in selectively recording interrogations, they would hardly be worth putting entire prosecutions in jeopardy, the argument goes.

Kathy Patterson (D-Ward 3), chairman of the Judiciary Committee, said the police should have followed the law from the outset.

"When your major law enforcement agency doesn't comply with the law, that's a problem," she said.

The proposal covers murder, rape and other serious crimes. Barely 20 percent of the interrogations this year that should have been fully recorded were recorded even in part, according to a report submitted by the police to the council.

After listening to testimony from Michael Anzallo, superintendent of detectives, Patterson said she was encouraged but nevertheless believed the time had come to put real force behind the law.

"It looks like they may finally be complying," Patterson said, "but I think enough time has passed to do this statutorily."

The D.C. Public Defender Service and the D.C. Association of Criminal Defense Lawyers support the proposal to strengthen the requirement.

The D.C. police, the U.S. attorney and the D.C. attorney general oppose the new law and laid out their objections during the hearings earlier this week.

All three agencies said they agree that routine video recording is a step toward sounder, stronger criminal prosecutions.

But they do not think the practice should be required by law and certainly not with the consequences that have been proposed.

Sometimes, it isn't possible to video record a suspect's statements, Anzallo testified. For instance, investigators may be interrogating a suspect as they drive around to identify burglary locations. Or the recording equipment may malfunction.

But the record of the department so far suggests that it was more than just faulty equipment that slowed the implementation of the order.

"It was simply a resistance to change," Patterson said.

In the report to the council, the department acknowledged that the requirement had not been implemented consistently, despite "good-faith efforts" to comply. As a result, four commanders were reprimanded.

What has been a more common practice in the District, and in some other jurisdictions, is to interrogate a suspect off camera for hours and record only when the suspect is prepared to provide what investigators believe to be a truthful account.

Many defense lawyers and some prosecutors criticize such tactics. Almost inevitably, defense lawyers raise questions about what other statements a defendant made earlier in the interrogation and why those statements were not recorded.

Defense lawyers may also raise questions about whether a suspect was threatened or assaulted before admitting to a crime.

Advocates of video recording say opening up the interrogation process not only reduces the likelihood of such misconduct but also limits pretrial litigation over allegations of misconduct.

"The core principle in this bill is openness," Julia Leighton, general counsel for the Public Defender Service, said in a statement.

"Juries and judges should be able to see what happens during an interrogation and decide for themselves whether the resulting statements are trustworthy and believable," she said.

The bill is expected to be voted on in committee the week of Nov. 29 and go before the council for two votes in December.