When Allen Logan's dreams of a nightlife empire began to fall apart, the ex-convict and entrepreneur embarked on a murderous rampage in Northwest Washington, prosecutors said.

Feeling betrayed by a would-be business partner whose promises of financing never amounted to anything, Logan turned his fury on the man's family, prosecutors said, killing his 20-month-old son and the boy's 80-year-old "Granny."

It was, prosecutors said, a horrific loss of life, and yesterday, a D.C. Superior Court judge sent the 34-year-old barber-turned-businessman to prison for the rest of his life.

The jury in the case had found the murder of little Mikea Washington "especially heinous, atrocious or cruel," which made Logan eligible for life without the possibility of release.

Such sentences are rare in Superior Court, even in murder cases. But the prosecutors, assistant U.S. attorneys Charles W. Cobb and Glenn L. Kirschner, argued that Logan had "shocked . . . the conscience of the community" and deserved to be "imprisoned forever."

Logan, who has admitted fighting with Mikea's father, Amin Washington, continued yesterday to insist that it was Washington who inadvertently killed his own son in the midst of the fight June 14, 2002.

When they met, Washington seemed to be the answer to Logan's prayers. Logan wanted to open a restaurant and nightclub, to be called Platinum World. He had incorporated, developed a business plan and assembled a board of directors. But he needed more money than his investors had put up. Washington promised to provide Logan with what he needed.

But Washington was a "con man," Cobb said yesterday. The money never materialized, and Logan, prosecutors said, was angry.

Standing yesterday before Chief Judge Rufus G. King III, who presided over the trial, Logan said he did deserve some of the blame for the fight but not for the deaths that ensued. "I do feel a lot of remorse about what happened," Logan said. "I say to myself, 'Why didn't we just meet at the office?' "

But they didn't, and prosecutors argued during the trial that Logan had set out that day for Washington's rowhouse in the 1400 block of Spring Road NW with anger and violence in his heart and left a bloodbath in his wake.

A toddler was dead. An elderly woman was dying. And a father, wounded in the attack, was left to wonder what more he could have done to save his son. Logan, prosecutors said, had used the child to try to lure Washington out from a hiding place, threatening to kill Mikea if Washington did not emerge. "Daddy, Daddy," the child cried out, and then fell silent, according to testimony in the case.

The violence was witnessed by Mikea's sister, then 4. In court yesterday, prosecutors played a video recording of a social worker's interview of the child. In it, the girl said, "Someone stabbed Mikea in the throat."

Logan, of Northeast Washington, was in violation of his probation on destruction-of-property charges at the time of the killings. He was arrested soon after the slayings. But the road to trial was long and unpredictable. He fired previous court-appointed attorneys and, for a time, demanded to represent himself.

Last fall, the case finally went to trial before Judge John H. Bayly Jr. but ended in a hung jury. In the spring, the case ended up before King for a retrial. The jury convicted Logan of murdering Mikea and Simona Druyard, 80.

Druyard's daughters, Altagracia Montilla and Alba Trott, came to court to speak for their mother and to seek justice for her.

"I don't have the words to express the destruction of my family," said Montilla, whose remarks were made in Spanish and translated for the court. "My mother was everything for me. . . . I just leave everything in the hands of justice and in the hands of God."