They call her Baby Channing.

Residents of the neighborhood named her after the street where she had been abandoned a year ago in Northeast Washington — a week, maybe two weeks old at most — naked, bleeding from the nose and mouth and wrapped in a bath towel. Temperatures that night dipped four degrees below freezing.

Three D.C. police detectives have put in hundreds of hours and built a case file six inches thick, but have yet to find the girl’s mother or any other relative or family friend. The infant died about three hours after she was found shortly before midnight on Jan. 15, 2012, her death ruled homicide by hypothermia.

Frustrated and out of leads, D.C. police are making a fresh appeal to the public to learn who left the infant outside a white picket fence at a duplex occupied by a middle-school teacher with two young children of his own.

“This must weigh on somebody’s conscience pretty heavily,” said Ian Milne, 32, who lives in that duplex in the 3000 block of Channing Street NE. The area is the Gateway neighborhood off New York Avenue and Bladensburg Road.

“You think somebody must know something,” Milne said Saturday. He remembers his neighbor knocking on his door after spotting the bundle while walking home from buying cigars. The sleepy Milne stumbled to his porch to watch as paramedics loaded the unconscious infant into the back of an ambulance, while the father of the man who found the infant, a preacher, began to pray.

Milne and his wife have two children, a 3-year-old boy and a 4-year-old girl, and the couple has spent the past year trying to adopt a third child. “It’s so tragic,” said Milne, who teaches at a charter school. “We’ve been on a list for adoption for a year and here somebody leaves, abandons, a baby at our front door.”

Police officials describe the lead detective, Jed Worrell, with a decade of experience investigating murders, as passionate about this case. In one recent meeting, he showed the chief a photo of the little girl. “He is really doing everything possible to close this,” Chief Cathy L. Lanier said. “We just need a new break.”

Lt. Robert Alder, commander of the homicide unit, said police are stumped. “We wish we knew more,” he said. “We have gone through all the tips. We have gone through all the leads.”

Alder said detectives have scoured schools, hospitals and neighborhoods, handing out reward fliers and knocking on doors, hoping to find somebody who knows somebody who was pregnant one day and not pregnant the next and with no baby to show. They’ve gotten dozens of such tips, Alder said, but none has panned out.

Police have the infant’s DNA, but because of privacy laws they cannot run her genetic code through a database in hopes of finding a hit. Such testing, called a familial DNA test, is considered in many jurisdictions to be an invasion of privacy that could too easily be abused by authorities.

But police have been able to do DNA tests on people whose names came up during interviews and who consented to them. None has any connection to the baby, he said.

The towel the child was wrapped in also has not been much help. It’s a generic, medium-sized towel with brown and red stripes, Alder said, and police been unable to trace where it came from. He said forensics tests do not reveal any pertinent evidence. Authorities are offering a reward of up to $25,000 for information that leads to whomever abandoned the infant.

The District has a safe-haven law allowing parents of unwanted babies who are less than a week old to drop them off at hospitals, firehouses or police stations without risk of prosecution, unless there is evidence of child abuse.

While Gateway residents gave the baby a name and held a candlelight vigil for Baby Channing, detectives in the homicide unit are sticking to convention. They call her Baby Jane Doe. Alder said he doesn’t know what happened to her tiny body, though he said he believes she was cremated.

“We would have liked to see her given a burial,” the lieutenant said.