Prosecutors dropped a first-degree murder charge yesterday against a man who was accused of killing a 66-year-old pastor last month in Northeast Washington.

Authorities do not have enough evidence to proceed with the case against Samuel Davis III, said Channing Phillips, a spokesman for the U.S. attorney's office. Davis's attorney contended that he was somewhere else at the time of the shooting, and police must now seek other leads in the slaying of Fletcher M. Lyles.

Davis, 24, of Northeast Washington has been jailed since his arrest Aug. 24, four days after Lyles was fatally shot at a gas station. But he isn't going free. Late yesterday, prosecutors charged him with assault with intent to kill in an unrelated shooting.

Lyles was killed in the early morning hours of Aug. 20 at the Citgo station in the 3800 block of Minnesota Avenue NE. Lyles, pastor of Mount Zion True Grace Church of Christ, a small church near his Southeast Washington home, was on his way to his day job as a construction supervisor when he stopped to fill up his pickup truck about 4:30 a.m.

He came upon a fight and was shot in the chest when he tried to intervene, according to police. He died about an hour later.

A judge signed a warrant for Davis's arrest on the basis of two witnesses who identified Davis as the gunman, court documents show.

At Davis's initial hearing, his attorney at the time, Anthony Matthews of the D.C. Public Defender Service, argued in vain that the witnesses' identifications were unreliable.

Yesterday, at a preliminary hearing to review the merits of the case, Assistant U.S. Attorney Tonya A. Sulia informed D.C. Superior Court Judge Ann O'Regan Keary that the government was withdrawing the charge.

Charles Daum, who replaced Matthews as Davis's attorney, said yesterday that Davis was a block or two away when the shooting unfolded and was innocent.

Daum said that he took on the case after he was contacted this month by the defendant's mother. She told him that she knew of witnesses who could exonerate her son, Daum said. Daum sent an investigator to talk to the other witnesses.

Their accounts placed Davis away from the scene, Daum said.

After police and prosecutors spoke to the new witnesses and reviewed other evidence in the case, senior officials at the U.S. attorney's office decided to drop the charge.

Daum said that the new witnesses had to give investigators pause. "I think the police department took a second look or a third look and they became convinced that their first two witnesses were in error or were perpetrating a falsehood," he said.

For Ethel L. Lyles, wife of Fletcher Lyles, the news that the charges had been dropped only deepened the sadness that has come with her husband's death.

"I'm a little disappointed that they didn't have the right man," she said, "but I sure hope they do get the right person. I really do. I don't understand how this could have happened, but I'm praying that they get the right person."