Courts and police in the nation’s capital will change how they conduct lineups of suspects, when they notify defendants about informants and how long they retain criminal trial records, all in response to errors that have put innocent people in prison.

A task force created by D.C. Superior Court Chief Judge Lee F. Satterfield recommended that police use computers and staff not associated with a particular case to administer photo lineups to prevent influencing potential witnesses.

The court acknowledged that DNA often has cleared defendants long after their convictions, so officials will by March begin keeping trial records permanently rather than destroying them after 10 years.

Local courts also will begin giving criminal defendants earlier notice of any information that might impeach police informants — such as their criminal record and whether they have been paid, won a plea deal or other inducement, or cooperated with police or prosecutors in the past. Such information will be turned over at least two weeks before trial if it does not endanger witnesses, officials said. Previously, defendants got that information a few hours or days before trial.

“The Superior Court strives to attain exemplary standards of practice in the criminal justice system,” Satterfield wrote in a letter Tuesday thanking the panel.

The changes place District authorities on a path undertaken by many state legislatures, police agencies and court systems in response to wrongful convictions discovered in recent years.

Eyewitness misidentifications have played a role in more than 70 percent of 301 DNA exonerations since 1989, a reminder that despite their persuasive power for juries, witness recollections are not always accurate. Erroneous testimony by jailhouse informants also has been a well-known problem.

Measures to correct the problem have not always kept pace. For instance, the D.C. Superior Court has not reviewed its records retention policy since 1984, before DNA testing in criminal cases.

Meanwhile, the District has seen a spate of recent mistakes. Satterfield formed the committee in response to requests by the D.C. Public Defender Service after the December 2009 exoneration of Donald Eugene Gates.

DNA tests showed that Gates spent 28 years in prison for a rape and murder he did not commit. His conviction was based in part on the testimony of a paid police informant and an FBI agent’s mistaken forensic testimony that he found Gates’s hair on the victim.

Since then, two other District men, Santae A. Tribble and Kirk L. Odom, were exonerated through DNA tests last year after spending a combined 50 years in prison. Mistaken FBI forensic hair matches helped convict both men. Tribble’s prosecutors additionally relied on an informant who received a plea deal, and police in Odom’s case used a victim’s testimony after she was shown Odom’s photograph several times.

U.S. Attorney Ronald C. Machen Jr. welcomed the recommendations, adding that his office is reviewing hundreds of cases for any similar forensic testimony errors but has found none.

“In addition to remedying past wrongs, we understand the importance of establishing best practices that will protect the integrity of our criminal justice system,” Machen’s office said in a statement.

Barry J. Pollack, president of the board of directors for the Mid-Atlantic Innocence Project, called the moves “a good step,” adding, “I applaud the effort.”

The 14-member committee was led by Superior Court Judge Russell F. Canan, former presiding judge of the criminal division, and included judges, prosecutors, defense lawyers, police, D.C. Council Chairman Phil Mendelson (D), aides to the deputy mayor for public safety and Pollack’s group.

Panel members generally agreed that the D.C. Innocence Protection Act, which took effect in 2002, is working well. However, the panel will continue to meet twice a year and review issues, acting as an ongoing, ad hoc “innocence commission.”

The panel stopped short of recommending more wide-ranging changes, such as expanding access to DNA testing or altering police evidence retention policies, saying they were not needed. However, they urged police to respond to research showing that new techniques can reduce mistaken identifications.

D.C. police said they will launch a pilot study in robbery cases of having photos presented “blind,” or by someone who does not know which suspect is being shown to a witness.

However, the panel said more study is needed before recommending that photos be shown one by one, or sequentially, to witnesses rather than simultaneously in a lineup.

Lawmakers in North Carolina and Ohio have mandated the use of blind sequential identification statewide, and police have voluntarily adopted similar measures in Dallas, Virginia Beach, Northampton, Mass., Winston-Salem, N.C., Burlington, N.C., and Wisconsin.

Twice since 2008, the District’s elected council has declined to mandate such a step, although Mendelson reintroduced the measure in his first act as chairman last year. D.C. police say sequential identification is an option for detectives, but public defenders say the practice has not been observed in the field.

“More work needs to be done, but we regard this as a good beginning” in addressing two leading causes of wrongful convictions, said Sandra K. Levick, chief of special litigation for the D.C. Public Defender Service.