With three acquittals and a hung jury in the trials of Baltimore police officers charged in the arrest and death of Freddie Gray, prosecutors face steep hurdles to winning convictions in the three remaining cases, legal experts said.

Circuit Judge Barry G. Williams, who cleared Lt. Brian Rice of all charges Monday, sent a strong message that the state's attorney's officelacks the evidence to prove the officers' conduct was criminal, observers said.

“The state is not simply 0 for 4,” said defense attorney Warren Brown, who is not involved in the cases but has observed the proceedings. “They're 0 for 24 when you add up all the charges that the judge or jury considered through thecourseof four trials.”

Rice, 42, was found not guilty of involuntary manslaughter, misconduct in office and reckless endangerment. Williams had dropped a charge of second-degree assault at the trial's midpoint.

“The judge has said over and over and over again [that the evidence] falls short of convincing him beyond a reasonable doubt” that the officers are criminally culpable, Brown said.

That doesn't necessarily mean prosecutors should drop the remaining cases, one expert said.

University of Maryland law professor Douglas Colbert said the trials are sending a message to police. Prosecutors should keep going after adapting their strategy based on Williams' latest ruling, he said.

“It would be irresponsible not to continue prosecution as long as our elected official believes that there's evidence to satisfy the burden of proof beyond a reasonable doubt,” Colbert said, referring to Baltimore State's Attorney Marilyn J. Mosby. “An elected official cannot fall to the public pressure being placed by the police union and others.”

Several challenges for prosecutors have emerged through the trials so far:

Williams has agreed with defense arguments that a crowd that formed around the arrest scene gave officers reasonable cause to use their discretion not to adhere to the department's police general orders on using seat belts.

Williams has said medical evidence was unclear about when exactly during Gray's ride in the van his injuries occurred.

He has said that the state can't prove that police were aware of new department rules, issued just days before Gray's arrest and which took away officers' discretion about putting seat belts on detainees.

And the judge has said that failure to follow general orders is not in and of itself a crime, particularly without being able to show that those rules were recklessly disregarded rather than a mere error in judgment.

Prosecutors and defense attorneys are barred from speaking publicly about the cases because of a gag order imposed by Williams.

Officer Garrett Miller, who observed Monday's ruling, is the next officer scheduled to be tried. Miller's case is fraught with new challenges for prosecutors: Because they compelled him to testify under immunity at the trial of Officer Edward Nero, a new team of prosecutors was appointed to handle his case.

Before his trial, the court will hold a hearing where prosecutors will have to prove that they were not exposed to any of Miller's testimony. During the process in which prosecutors lobbied to compel Miller to testify, Williams, the Maryland attorney general's office and the Court of Appeals all said prosecutors face a high bar at such a hearing.

Officer William Porter also was compelled to testify, and his retrial also will require such a hearing, known as a “Kastigar hearing.” The third officer who still has pending charges is Sgt. Alicia White.

Miller's case focuses on Gray's initial detention and arrest. Nero was already acquitted for his role in arresting Gray, and prosecutors dropped a charge against Rice related to that aspect of the case.

Williams left some room for prosecutors in Miller's trial, finding that Nero did not participate directly in the arrest without rejecting prosecutors' argument that the detention was illegal. Still, he skeptically questioned prosecutors during closing arguments of Nero's trial.

David Jaros, a University of Baltimore law professor who has been observing the trials, said prosecutors' best hope might be if Miller made an incriminating comment in his statement to investigators.

“This is a hard case,” Jaros said. “There are reasons to have doubts about what happened.”

But Jaros said people watching the cases shouldn't interpret Williams' verdicts as absolving the officers of wrongdoing.

“The judge made it clear that just because you made a mistake — someone may have done something that was very wrong, that was very inappropriate — but that doesn't necessarily make it a crime,” Jaros said.

“If you do something that is grossly unreasonable, but you're not aware of the risk you're taking, you're not being grossly criminally negligent, even though you're being negligent,” he said.

Williams repeatedly stressed Monday that there was a difference between civil negligence — finding that the officers' conduct caused Gray's death — and criminal liability — determining that their conduct had been so reckless, with results that could have been anticipated, that they should be convicted of a crime.

“To say there's a tragedy, therefore somebody has to be criminally responsible, is really an inappropriate manner to approach this case,” said Brown, the defense attorney.

David Harris, a University of Pittsburgh law professor who studies racial profiling and police misconduct, said that while he is “strongly sympathetic that police ought to be held accountable for wrongdoing,” prosecutors have proceeded with a legally dicey case.

“The American legal system is very reluctant to hold anybody, not just these police officers but anybody, criminally responsible for not doing something,” Harris said. “Criminal law is not always the best tool available. Many times it feels like it should be, when there has been a parade of injustices over so many years. But any given case depends on its facts and evidence.”

Colbert thinks prosecutors can dig into their evidence and find something to satisfy what Williams is looking for.

“I have to believe that evidence is available, and I hope we get to hear it at the next trial,” he said.

Defense attorneys in the cases so far have asked, before the beginning of the trials, for Williams to dismiss charges. Warren Alperstein, a defense attorney and former prosecutor, said judges can't dismiss a case based on their views of a previous trial.

“No judge can control whether or not the state goes forward with any case,” Alperstein said.

“I don't see a scenario where any of these cases are going to be dismissed by the court. The only way the cases are not going to go forward is if the state elects to dismiss them.”

jfenton@baltsun.com