Two months shy of her second birthday, Tiffaney Henderson was shaken and beaten to death.

Karen Wills, a 20-year-old aspiring model, was shot in the head as she walked through her boyfriend's house.

The body of 14-year-old Sterling Settle was found off a logging road in western Charles County. He had been shot to death four days earlier.

Each of these deaths led to a homicide ruling by state medical examiners. Each time, Charles County sheriff's office detectives descended on the death scenes, interviewed witnesses and family members and searched through homes for evidence. They looked for the little details that could lead to an arrest, a conviction, a measure of justice.

Each killer, though, has so far gotten away with it.

The deaths of Tiffaney Henderson, Karen Wills and Sterling Settle remain open in the sheriff's office cold case file. And in the past eight years, more homicide cases have had the same results -- a killer on the loose, frustrated detectives and a heartbroken family denied justice.

An unsolved homicide was once rare in Charles. Between 1975 and 1994, detectives solved all but five of the county's 88 homicides, a 94 percent closure rate.

But since 1995, 12 homicide cases remain unsolved, and the closure rate dropped to 76.5 percent of the 51 slayings during that period. It is still a much higher percentage than in Washington or Prince George's County, where the rates have hovered around 50 percent of homicide cases solved for the past few years. The national average is 63 percent, according to the FBI.

Charles's closure rate is lower than some nearby counties. Montgomery County's rate is consistently above 80 percent. In Anne Arundel County, police solved all of their 11 homicides last year. St. Mary's County has had no unsolved cases in the past eight years, and Calvert County has one open homicide case, the 1997 shooting death of Milton Harrod.

"I wish ours was 100 percent," said Capt. Samuel N. Graves, commander of the sheriff's criminal investigations division in Charles.

Once, killings in Charles County were most often crimes of passion. Domestic disputes between husbands and wives, boyfriends and girlfriends, fathers and sons accounted for most homicides, and those killings usually yielded lots of physical evidence, a motive, an obvious suspect and a quick arrest.

Detectives want to be able to solve a homicide within 72 hours, Graves said, before important evidence and witnesses can vanish. But in the 1990s, Charles began seeing more difficult cases involving long investigations and little evidence.

Of the 12 unsolved cases, six are possible body dumpings (someone killed elsewhere whose body is left in Charles County), three may involve strangers and three are child abuse deaths. In one case, detectives have not even been able to identify the victim, a black woman whose body was found in 1998 in Bel Alton.

These types of cases are harder to solve than domestic disputes, criminology experts said.

"It's so hard to get the information needed" in such cases, said Charles Wellford, chairman of the Criminal Justice Department at the University of Maryland. "There is no motive. There are no witnesses. Those things are very, very hard to overcome."

Take the case of Karen Sabrina Wills, who was fatally shot on Sept. 4, 2001. She was washing dishes after a late dinner of broccoli and cheese with her boyfriend, Gary Gray, when at least three shots were fired from outside the house on King's Wharf Lane in the Wakefield neighborhood of St. Charles.

One bullet went through the kitchen window and wooden blind before fatally wounding Wills in the head about 1:30 a.m.

Charles County detectives immediately went to work, marking with orange chalk where bullet fragments had fallen, interviewing neighbors and checking into Wills's past and current relationships. For a time, investigators suspected a past boyfriend of Wills's who had threatened her with violence, according to law enforcement sources.

But now, because a shooter would not have been able to see Wills through the blinded windows, some believe the person who shot Wills may have been a stranger. Linda Thomas, Wills's aunt, said her niece "had no enemies."

"Because of how it happened, we're not sure she was the target," Graves said. "No one could have seen that she was behind that wall."

With no witnesses, no motive, no suspects, the investigation stalled.

A child abuse death also poses difficulties.

Tiffaney Henderson was rushed to the hospital on Dec. 16, 2001, with severe head trauma and bruises all over her tiny body. Antoine Henderson, her father, said she had a purple ring around her eye and bruises on her hip and head, which had been shaved at Children's Hospital so doctors could put her on life support. She died eight days later on Christmas Eve.

Charles County detectives had suspects right away in Tiffaney's death, according to sources and county documents.

Her mother, Theresa Brooke, and Brooke's boyfriend, Eric Gibbons, were the only other people in the Waldorf townhouse when Tiffaney suffered her injuries, sources said. Jonathan L. Arden, the chief medical examiner in the District, dismissed their assertions that Tiffaney died after a fall down stairs. And an affidavit signed by two Charles County Department of Social Services workers on Dec. 27, 2001, asked that Tiffaney's younger brother be taken away from Brooke and Gibbons because Gibbons was "the alleged abuser" in Tiffaney's case.

But an arrest has yet to be made. The social services affidavit and law enforcement sources have described Theresa Brooke as "uncooperative" in the investigation. Brooke and Gibbons did not return calls seeking comment.

Charles County State's Attorney Leonard C. Collins Jr. said authorities often must rely on the details that medical examiners provide. And without witness testimony or a confession, a child abuse death can go unsolved, said Robert Kirschner, a former Chicago medical examiner who is considered an expert in child abuse.

"They require a lot of work and a lot of investigation," Kirschner said.

For victims' families, the wait for an arrest is difficult.

Antoine Henderson, 29, said he thinks about his daughter every day, how she would toddle around on the basketball court, or pull her hair when she laughed. Mostly, he said, he thinks about her death.

"I wonder how it happened. Why did it happen . . . and why the police aren't doing anything about it," said Henderson, who lives in St. Charles. "I feel like it's never going to end."

Wills's relatives said they are impatient for someone to be punished for cutting short a promising life. Wills, slim and attractive, was beginning to make good money as a model when she was gunned down, said Thomas, her aunt.

"How long is it going to take?" asked Thomas. "Any day, I could be talking to my niece's murderer."

The cases that the county does solve result in strong convictions. In all but one of the more than 40 murder cases brought to court since 1995, there has been a verdict of first- or second-degree murder.

"That's another sign the department is doing well," said the University of Maryland's Wellford.

At the sheriff's office, the four detectives in the crimes against persons unit are constantly reminded of the open cases. On the south wall of the unit's office, there is rectangular marker board with the names of homicide victims. Closed cases are marked in black ink, open cases in red ink.

Red cases sometimes turn to black only after years of investigation. Consider the death of Michael Harley, 19, whose body was found in some woods in Brandywine in August 1998. Prince George's police immediately made an arrest and charged a 17-year-old with murder.

Ten months later, Prince George's let the teenager go when Charles County detectives told them they were convinced the killing actually took place in Waldorf. An informant who knew the detective working the case came forward, saying he knew who killed Harley, Collins said.

Three years later, Charles County made an arrest in Harley's case after another break: The girlfriend of the main suspect, Kenneth Williams, finally told police what she knew, Collins said. She had been assaulted by Williams, Collins said, and detectives seized on her change of heart.

"Hard work makes its own lucky breaks," Collins said.

Antoine Henderson's daughter Tiffaney died after being injured in her mother's home. Henderson said he thinks about Tiffaney and her death every day. Sterling Settle

Found dead

Oct. 13, 1995

Carl Gillespie

Found dead

Aug. 5, 1996

Elizabeth Sloane

Found dead

Oct. 6, 1997

William M. Brown

Found dead

Dec. 5, 2000

Karen Wills

Fatally shot

Sept. 4, 2001

Tiffaney Henderson

Died of head injuries

Dec. 24, 2001

Darwon Curtis

Found dead

July 15, 2002

Detective Vince Shoemaker is working two of Charles County's 12 homicide cases that have gone unsolved since 1995.