Prince George's County State's Attorney Angela Alsobrooks talks with Del. Melony G. Griffith, the chair of the Prince George's County delegation, during a visit in Annapolis. (Mark Gail/The Washington Post)

Angela Alsobrooks had not been in a courtroom — at least not at the prosecutors’ table — for more than a decade. As she poured herself a cup of ice water before her opening statement, her hand shook so violently with nerves that a colleague heard the cubes rattling in the pitcher.

The jurors marched in. Alsobrooks, the Prince George’s County state’s attorney, brushed her hair from her face and began telling them why they should convict a D.C. police officer of killing his mistress and then leaving their infant daughter in a hot SUV to die.

“What is done in darkness surely will come out in the light,” she started.

Since she was elected in 2010, Alsobrooks has operated largely behind the scenes in a prosecutor’s office that is among the region’s busiest. This case — the first she tried personally since she took office — thrust her into the spotlight in a new way.

A conviction would demonstrate that the county’s first woman state’s attorney is as much dogged prosecutor as she is skillful politician. But what would she say to the lawyers who worked for her if she lost? What would she say to the family of the victims, a 20-year-old aspiring sheriff’s deputy and her 11-month-old daughter?

“I thought the evidence was strong, but you never know with a jury. Never,” Alsobrooks said in an interview later. “I just desperately wanted to bring peace to this family.”

Stepping into a challenging role

When Alsobrooks, 42, became the county’s top prosecutor in January 2011, she said her goal was simple: Make sure “we’re not in here flubbing cases.”

She had worked there about nine years earlier, prosecuting domestic violence cases, and she knew the challenges.

Historically, jurors are distrusting of authorities in Prince George’s, and many cases are complicated by the uncooperative, undependable or frightened witnesses that come with street crime in an urban area. And the caseloads are heavy. The office, with a $14 million budget, has 80 prosecutors handling 47,000 cases a year. Montgomery County, by comparison, has 80 prosecutors handling 25,000 cases.

Now more than halfway into her four-year term, Alsobrooks has staked a reputation as a capable leader — one who balances the duties of raising a young daughter, managing prosecutors and lobbying legislators.

Even before she took office, Alsobrooks hired a tough former prosecutor to be her “eyes and ears” in the courtroom, popping into trials unannounced to critique attorneys and give advice. Prosecutors say they feel more rigorously evaluated than ever before, and that the issues important to them are well-represented in the statehouse, where Alsobrooks is pushing for new laws on mass threats and gun crimes.

“Angela keeps abreast of everything that’s going on, especially with these significant cases,” said Assistant State’s Attorney Joseph Ruddy. “She does give input when she needs to. And she does make sure that the direction of the case is heading where it needs to go.”

But her office has had mixed success at trial. It hailed a conviction against a man who gunned down a popular Maryland state trooper but was stunned when jurors found that a Bowie State University student charged with murdering her roommate had acted in self-defense.

The office does not keep data on overall conviction rates. But prosecutors won convictions in more than 90 percent of homicide cases so far this year, compared with 84 percent last year and 88 percent in 2011, authorities said.

“The true goal of it is to have a community that is free of crime,” Alsobrooks said. “I think we’ve contributed to the decline in crime, because people are now incarcerated.”

A passion for the work

The daughter of a newspaper distributor and a receptionist, Alsobrooks grew up in Prince George’s and the District and was elected class president in high school. She was clerking for a Baltimore judge after her 1996 graduation from the University of Maryland law school when an aggressive prosecutor caught her attention. “I loved her passion and her fire, and I said, ‘You know what, I think that’s what I’m going to do,’ ” Alsobrooks said.

Friends say Alsobrooks has the same intensity. “Angie can get really feisty when she wants to,” said longtime friend Erica Berry. “She’s petite, but she’s packing a lot of power.”

In 1997, Alsobrooks went to work for then-Prince George’s County State’s Attorney Jack B. Johnson, a relationship that springboarded her political career. Elected county executive, Johnson brought Alsobrooks with him — first as an education adviser, then to run the county’s Revenue Authority.

Alsobrooks, who earns an annual salary of $150,000, credits connections from those jobs with helping her win a hotly contested election for state’s attorney. She said she was “surprised and disappointed” when she learned that Johnson, who is now serving a more than seven-year federal prison sentence, had taken as much as $1 million in bribes.

“He was a mentor and he helped me, so I don’t ever want to be dishonest about that,” Alsobrooks said of Johnson.

As a prosecutor, Alsobrooks prides herself on weeding out corrupt police officers. She grew up hearing a family story about how her great-grandfather was fatally shot — for no apparent reason — by a law enforcement officer in South Carolina. Because of that, she said, she has been unafraid to charge people who work for the county police department.

“She’s very resolute in what she does,” said veteran homicide prosecutor Wesley Adams. “She can get her mind made up, and she can very much be the immovable object.”

In the most high-profile of those cases, Alsobrooks pushed to indict two Prince George’s police officers in the beating of University of Maryland student John McKenna during a raucous basketball postgame celebration. The beating, which was captured on video, occurred months before Alsobrooks took office, and some wondered whether the investigation had stalled.

Jurors ultimately convicted one officer and acquitted the other.

Terrell N. Roberts III, the attorney for McKenna, said he credits Alsobrooks with finally bringing charges but said the prosecution was shoddy.

“I don’t think they devoted enough resources to the case to really get a conviction,” Roberts said. “I’m flabbergasted that the one officer was acquitted. You watch the film. He’s striking this kid, and the kid is defenseless and not moving a muscle. And somehow there’s an acquittal there? That doesn’t make any sense to me.”

Alsobrooks said prosecutors worked hard to present a difficult case, and jurors “got to decide what kind of policing they would authorize.”

Taking a case personally

It was the crimes of D.C. police officer Richmond Phillips that so enraged Alsobrooks that she decided to prosecute him herself. Phillips was off-duty when he fatally shot his mistress and left their 11-month-old to die in a sweltering SUV. The married officer didn’t want to acknowledge the child or pay her mother child support, prosecutors said.

Alsobrooks has a special affection for children. In recent weeks, she has pressed legislators in Annapolis to pass legislation making it a separate crime to commit an act of violence in front of children. Her office is filled with pictures of her 7-year-old daughter, Alexandra Alsobrooks-Laney, who lives with her but spends every other weekend in the District with her father, according to both parents. Alexandra can sometimes be seen following her mother around the Upper Marlboro courthouse.

Alsobrooks called Phillips “evil.”

“He lured this woman out there in darkness thinking that nobody would ever learn about his misdeeds,” Alsobrooks said. “His whole life was dark.”

Jurors deliberated for less than two hours before convicting him of every charge against him. Alsobrooks said she cried.

“The relief is hard to explain that I felt standing at that table,” Alsobrooks said. “I don’t know what I would have done if there was no justice.”