Baltimore County Police Chief James W. Johnson

Baltimore County Police Chief James W. Johnson (Christopher T. Assaf, Baltimore Sun)

The call to the county homicide detective came in the middle of the night. A man had been gunned down at a bus stop on Eastern Boulevard in Essex. Found on the scene, the victim's cellphone held a message from someone named Ashley. It read simply, "You dead."

Like most homicide victims in Baltimore County, Robert Holiday knew his killer. Witnesses willingly spoke to investigators and testified in court. The result: three convictions in a year and a life sentence for Holiday's former girlfriend, Laquesha "Ashley" Lewis.

Baltimore County police claim a 100 percent homicide clearance rate last year, about double the figure from Baltimore City. While urban and suburban homicide units face dramatically different realities and challenges, Baltimore County stands out even among its suburban peers. Across Maryland, the homicide clearance rate is 61 percent.

The reasons are varied. Random acts of violence are rare in the county. Gangs — whose codes of silence are hard to break — are less prevalent as well. But Baltimore County has also won national attention for a set of novel investigative policies that officials say have helped them capture more killers.

A recent Bureau of Justice Assistance report cited several policies as models for other agencies. For instance, the county assigns the beat officer who initially responded to the call to the homicide unit's investigation to offer expertise about the scene or the neighborhood.

The report also noted that the department records all investigative interviews. Those recordings can be played for jurors in court, and can be helpful if witnesses become reticent or change their stories before trial. Baltimore City — where witnesses often recant or are reluctant to testify — has begun using a similar tactic in serious crimes.

Such recordings played a major role after Holiday's death in February 2013. The lead homicide detective was wearing a recording device when he spoke with one of the suspects on the street. Played in court, the tape provided an unvarnished look at the encounter, giving jurors context beyond police testimony.

County officials also credit the work of the Police Department in preventing crime and solving cases.

Police Chief James W. Johnson said the relatively low homicide rate and high clearance numbers reflect the work of his agency and the cooperation of the community.

"It's about who you hire, how you educate them, how you constantly evolve, developing their skills, putting the right people in the right position," he said.

Annual homicide clearance rates measure the total number of homicide arrests — even in cases from previous years — against the total number of killings recorded over 12 months. Though county police said they solved 16 of 20 homicides that occurred in 2013 — 80 percent — arrests from prior slayings increased the rate.

Clearance rates are something of a different issue in cities like Baltimore, which experienced 235 murders last year. Officials and other experts say city cases can be more difficult to solve. Police say many are linked to drugs or gangs, which can leave witnesses afraid to testify.

Charles Wellford, a University of Maryland criminologist, said gang-related homicides are extremely difficult for any locality, given the reluctance of those involved to cooperate. In a domestic-related incident, the suspect is often still at the scene or there is evidence of past conflicts.

"When you have different [gangs] fighting it out, it's very hard to clear. Few jurisdictions have high clearance rates on those," Wellford said. "Domestic homicides are easier."

In 14 county homicides last year, detectives were able to determine that the suspects knew the victims in some way. Though the county cleared all of those homicides, Johnson said that factor alone does not necessarily bring an automatic arrest.

"You have to work hard to prove and bring a good solid case into the courtroom," Johnson said. "When you have two rival drug associates involved in a homicide, it takes a lot of work. They know each other, but these cases are very difficult."

Overall, killings in the county have dropped in recent years, with 2013 marking the lowest homicide rate per 100,000 residents since the 1970s.

The relatively low number of suburban homicides means that just one or two additional unsolved killings can cause wild swings in clearance rates from year to year.

Since 2006 Montgomery County, with 12 to 21 slayings per year, cleared 100 percent of its cases some years — and once as few as 40 percent. Anne Arundel County has reported from 10 to 18 homicides per year since 2006, with clearance rates ranging from 50 to 100 percent.

Baltimore County has consistently exceeded the state and national averages, a result that Baltimore County State's Attorney Scott D. Shellenberger recently attributed to good police work and lengthy sentences.