Hobbled by reluctant witnesses and distrust in corruption-plagued police, city prosecutors have dropped cases at a higher rate and won convictions at a lower rate under Baltimore State’s Attorney Marilyn Mosby than before she was elected.

Four years ago, when she challenged then-State’s Attorney Gregg L. Bernstein for the job, Mosby said convictions were essential to reducing what she called the “crisis” of violence in Baltimore. She upset Bernstein in the 2014 Democratic primary, in part, by arguing that he was losing too many cases.

Now, as she runs for re-election, Mosby’s challengers in the June Democratic primary — attorneys Ivan Bates and Thiru Vignarajah — are aiming that same criticism at her.

Mosby’s office has recorded a lower conviction rate — 92 percent — than Bernstein during the worst span of violent crime the city has seen in decades. Bernstein achieved a 95 percent conviction rate, while dropping fewer cases, during what was the city’s least violent four-year span since the 1980s.

Mosby’s office dropped 38 percent of cases from 2015 through last year, data shows. During the last two years under Bernstein, the only years for which The Sun has data, the office dropped 27 percent of cases.

The conviction rate includes only those cases that prosecutors moved forward with. It does not include dropped cases. Bates said, “That tells the criminal element they can get away with it.”

Mosby said her office is taking a holistic approach to fighting crime — not only prosecuting cases, but offering programs for youth and the community.

“We are on the forefront of progressive reform, and we need to be,” Mosby told The Baltimore Sun.

Deputy State’s Attorney Michael Schatzow, Mosby’s top deputy, says prosecutors have faced unprecedented turmoil in the Baltimore Police Department, making the job of city prosecutors more difficult.

Three months after Mosby was sworn in in 2015, Freddie Gray died in police custody, and the city erupted in riots. Mosby brought criminal charges against six officers in Gray’s arrest and death, but won no convictions.

Homicides spiked: The city has suffered more than 300 killings in each of the last three years.

The Justice Department found that the Police Department had engaged in years of discriminatory and unconstitutional policing, particularly in impoverished and minority neighborhoods, and the city agreed to a court-enforced consent decree requiring reforms.

Eight members of the elite Gun Trace Task Force were indicted and convicted of federal racketeering charges for robbing drug dealers and innocent civilians.

The respected Police Commissioner Darryl De Sousa, appointed in January to help reduce the violence and restore stability to the department, resigned last month amid federal charges he failed to file his tax returns.

Mosby is now working with her fourth police commissioner in less than three years.

“It’s like an infection that spreads and contaminates everything,” Schatzow said. “That results in more scrutiny, which results in more prosecutors exercising their discretion to perhaps not go forward with a case.”

He said police corruption has made jurors distrustful of police. In light of that distrust, Schatzow cast the fact that the conviction rate has fallen by only a few points under Mosby as a kind of victory.

“We should be down about 40 points,” he said.

Elaine Borakove studies conviction rates as president of the nonprofit Justice Management Institute in Arlington, Va. She said a rate of 90 percent or higher indicates success. Borakove also said a decline of 3 percentage points is insignificant.

Mosby’s office says the number of cases deemed not suitable for prosecution and dropped should not be counted against her.

Mosby told The Wall Street Journal two years ago that it was “shameful to take pride in overwhelming conviction rates. We are here to do justice and make Baltimore safer, not gloat.”

But her re-election campaign is using the 92 percent rate to argue that she has been successful. Rep. Elijah E. Cummings touts the number in a radio ad for Mosby, and she has tweeted a picture from her campaign headquarters of talking points that remind volunteers to mention it.

“If you’re looking to see whether I’m doing my job, we had a 93 percent conviction rate in 2016,” Mosby told The Sun after filing for re-election in February. “Last year, it was 92 percent.”

Schatzow called the decline in the felony conviction rate from 95 percent under Bernstein to 92 under Mosby percent “negligible.”

“What’s the difference between getting a 95 on a test and a 92?” Schatzow said.

In 2018, he said, the rate is hovering close to 95 percent. The 2018 numbers have not yet been released.

Mosby’s office prosecuted nearly 3,800 felonies last year and won about 3,500 convictions — including nearly 1,100 for attempted murder, assault, armed robbery, carjacking, arson and burglary.

Securing a conviction on any crime with which a defendant is charged counts toward the conviction rate, whether or not it was the most serious crime charged. Nearly all convictions come through plea agreements.

Mosby says her homicide unit won 78 convictions last year for a rate of 77 percent. A comprehensive homicide conviction rate under Bernstein was not available, but it was 71 percent during his first year in office.

Mosby has spoken repeatedly of a need to bolster support for victims and witnesses. Grant funding for such efforts has increased 29 percent during her tenure, she said. She has added staff to perform community outreach and recently celebrated improvements to the waiting room at her office.

Still, her office has dropped an increasing percentage of cases every year because of uncooperative victims and witnesses.

Under Bernstein, the office dropped 27 percent of cases for that reason. After Mosby took office, the percentage rose to 29 percent in 2015, 31 percent in 2016 and 34 percent last year.

Mosby beat Bernstein in the 2014 Democratic primary by 9 percentage points. City Republicans did not nominate a candidate; Mosby took 94 percent of the vote in the general election.

Now she faces Bates and Vignarajah in the Democratic primary June 26. Again, there are no Republican candidates, so the state’s attorney will likely be decided then.

Vignarajah, the former Maryland deputy attorney general, said statistics are only a starting point.

“It isn’t just about conviction rates,” he said. “It’s about whether we are charging and prosecuting the right violent, dangerous criminals. It’s about whether or not we are inflating our conviction rate by pleading out people to suspended sentences.”

Vignarajah, 41, has campaigned as a reformer, saying he would stop prosecuting addicts for petty crimes, support immigrants and oppose mandatory minimum sentences. He says he has a plan to cut homicides in half within three years.

He said that he would publish online weekly statistics of convictions and dropped cases.

Bates, 49, a longtime defense attorney, has called Mosby an ineffective crime fighter. He has campaigned on a strategy to aggressively prosecute violent criminals while providing drug and mental health treatment to nonviolent offenders.

He says prosecutors are waiting too long to drop flawed cases. He says he would include dropped cases in calculating his conviction rates.

Borakove, at the Justice Management Institute, warns that too much emphasis on conviction rates can lead to wrongful convictions. She says much of a state’s attorney’s effectiveness can be measured outside the courtroom.

Picnics hosted by Mosby and her visits to schools can also help fight crime, Borakove says. And so can Mosby’s fame. Mosby drew national attention when she brought the charges against officers in Gray’s death.

“It helps build public trust and confidence,” Borakove said, “when the prosecutor is recognizable.”

jfenton@baltsun.com

twitter.com/justin_fenton