Shortly after 8-year-old Chelsea Cromartie was slain by a stray bullet early last month, D.C. police Capt. Robert J. Contee publicly declared that detectives were "going to find out who is responsible for this murder."

Within about a week, two brothers were arrested and charged in her killing and the wounding of the girl's 38-year-old aunt.

Contee's promise was a bold pledge. He had only recently taken over as head of the police department's violent crimes branch, one of the most closely scrutinized and pressure-filled jobs on the force. At 31, he is younger than most big-city commanders of units that handle homicides, according to outside law enforcement specialists. He has little investigative experience.

Yet Contee and the department's chief are confident that the young captain will excel in handling such a demanding assignment.

Chief Charles H. Ramsey, who promoted Contee, said he has been impressed by Contee's encylopedic knowledge of homicide investigations and cool demeanor under pressure. He has set a high bar for the future.

"One day he will be chief of police here, if not somewhere else," Ramsey said.

One recent morning, Contee sat at his desk in his sparsely decorated office in Southeast. He listened to classical music as he reviewed reports and prepared for a daily crime meeting of commanders and detective supervisors.

A tall, thin man who wears tailored suits and shiny ties, Contee appears laid-back and easygoing -- a seeming anomaly for someone who works in one of the most high-pressure jobs on the force. A constant reminder of the position's demands hangs on his wall: a chart of the year's homicides and clearance rates. For years, the department has been criticized for not doing enough to solve murders.

Last year, police posted a 60 percent clearance rate, meaning that the total number of homicide cases closed was 60 percent of the number of killings for the year. In 2001, the department cleared 48.5 percent of cases. This year, the clearance rate so far is 55 percent.

The department has set a goal of 65 percent for the year.

Contee's job is mostly administrative. He attends meetings with detectives and his commanders and deals with prosecutors when disagreements about cases pop up. He also reviews files and tries to make sure his detectives get what they need to solve cases.

Stanley Farmer, a homicide detective, said he asked Contee on May 21 if he could have a class of police recruits search a District park for a weapon possibly used in a 2002 killing. Within two hours, Contee lined up a recruit class to scour the park the following week, Farmer said.

Contee already has overseen several high-profile cases. When 14-year-old Jahkema Princess Hansen was slain in January, Contee was attending a church youth retreat in Ocean City. Stuck on the Eastern Shore without a car, he spent the rest of that weekend on his cell phone, helping to direct the investigation and reporting its progress to his higher-ups.

He worked closely with school officials and detectives when 17-year-old James Richardson was slain in February inside Ballou Senior High School. When 8-year-old Chelsea was slain, Contee worked nonstop with his detectives.

"He's doing a very good job," said Contee's boss, Cmdr. Michael Anzallo, superintendent of the department's detectives.

"He gets along with those guys pretty well, but they still know he is the captain of the unit," said Anzallo, who preceded Contee in the job. "He takes a personal interest in their cases and their personal well-being. He's made decisions that are in the best interest of the department and people over there."

The detectives also respect him, said Sgt. Gregory I. Greene, chairman of the D.C. police department's labor committee in the Fraternal Order of Police Lodge 1.

"We've been hearing good things about him," Greene said. "A lot of the officers like him because he's one of those guys who will work, roll up his sleeves and get in the trenches with them."

Contee, who is married to a police officer in another division of the department, has three children and is raising a 9-year-old cousin. Contee was raised in Carver Terrace in Northeast Washington, an area of squat-looking apartment buildings once known for drug dealing, gang fights and shootouts.

Contee was not an enemy of the law during his youth -- his aunt was a District officer -- but he adhered to the code of the neighborhood and kept his distance from police, he said.

"You wouldn't see me kicking it with a police officer on the street," Contee said.

The son of a clerk at the U.S. Department of Housing and Urban Development and a homemaker, Contee was a member of the National Honor Society at Spingarn Senior High School in Northeast and participated in citywide student government. But he was unsure of his future until he happened to attend a job-orientation assembly.

On stage, a police officer was promoting a program that allowed high school students with enough credits to attend a half-day of classes and go through the police academy in the remaining time. After graduation, the students would be hired as civilian employees in the department. On their 20th birthdays, they would automatically become full-fledged officers.

Contee signed up almost immediately.

"Something about it just grabbed me," he said.

He has moved quickly through the police department, handling a variety of duties.

He began work as a patrol officer in the 3rd District and later was an undercover officer targeting businesses that sold alcohol to minors. Promoted to sergeant in 1997, Contee was assigned to patrol duties in the Georgetown area before heading to the police academy, where he ran part of the agency's training programs.

In 2000, he was promoted to lieutenant and worked again in Georgetown, then for an assistant chief in a regional command.

In June 2003, he was reassigned to supervise the department's 30-member intelligence unit, which handles sensitive investigations, the gathering of information on gangs and some anti-terrorism work. A little more than six months later, he was promoted to captain and put in charge of the violent crimes branch.

"It's tough work, but rewarding work, every time we take a murderer off the streets," he said of his new duty. "It's tough in the sense that you get to see how cold people can be, to be so reckless and take the life of somebody else without thinking twice."

Capt. Robert J. Contee, right, hopes to improve the crime closure rate in the D.C. police violent crimes branch. Above, he confers with homicide detectives, from left, Robert W. Alder, Lee E. Littlejohn and Christopher T. Kauffman.Contee, 31, has won praise from Police Chief Charles H. Ramsey, and from members of the rank and file.