After a Maryland judge declared a mistrial on Wednesday in the trial of Baltimore police officer William Porter, who was charged with involuntary manslaughter in the death of detainee Freddie Gray, a pair of top New York defense attorneys questioned whether Porter should have been on trial at all.

Baltimore City Circuit Court Judge Barry Williams issued the ruling after the jury of seven women and five men was unable to reach a verdict after about 16 hours of deliberations.

"The bottom line is, it's a lot easier for a grand jury to come up with an indictment than it is to convince a  a trial jury to convict beyond a reasonable doubt," said defense lawyer and Fox News legal expert Arthur Aidala."It doesn't sound what the prosecutors argued was egregious enough to drive a jury to a guilty verdict."

Gray, 25, was arrested after fleeing from police. He was put in a transport van, shackled and handcuffed, but was not secured by a seat belt despite department policy to do so. He died a week later.

Porter, who was a backup officer, testified that Gray told him he needed medical aid. Porter told the van's driver and a supervisor that Gray had asked for aid but none was summoned, according to testimony.

Porter was charged with involuntary manslaughter, second-degree assault, reckless endangerment and misconduct in office. 

"The prosecution took a big wide net and cast it over everyone who came in contact with Feddy Gray,"  said prominent New York defense attorney Joe Tacopina.  "There's no indication he [Porter] did anything wrong.

"He wasn't in any way directly responsible [for Gray's death]. By all accounts. he didn't do anything wrong."

Tacopina said he was surprised that prosecutors chose Porter as the first of six officers to be tried.

"Normally you start ofut with your best shot," Tacopina said.  "If this was their lead-off hitter, you have to wonder what's behind him in the batting order."

Aidala went even further, saying Porter should not even have been charged.

He said Gray was young and healthy with no apparent injuries and Porter had notified his boss that Gray asked for meedical attention.

"If we're going to put cops behind bars in cases like this, the hospitals will be loaded up every time there's and arrest," he said. "This is basically a civil case — that the Gray family has already won. They settled for $6 million. That's a lot of money."

Williams, the judge in the case, said an administrative judge would set a new trial date as early as Thursday.

Porter, who looked relieved after the ruling, said he would not appear at the scheduling hearing.

The panel said on Tuesday that it was deadlocked, but Williams told the jurors to keep trying to reach a verdict.

Porter is the first of six officers to be tried in Gray's death, from a broken neck suffered while he was transported in the back of a police van.

His death triggered protests, rioting and arson in the majority black city of 620,000 people and intensified a U.S. debate on police treatment of minorities.

Three of the six officers charged in Gray's death, including Porter, are black. Charges against the other officers range from second-degree murder for the van's driver, to misconduct.

Gray, 25, was arrested after fleeing from police. He was put in a transport van, shackled and handcuffed, but was not secured by a seat belt despite department policy to do so. He died a week later.

Porter, who was a backup officer, testified that Gray told him he needed medical aid. Porter told the van's driver and a supervisor that Gray had asked for aid but none was summoned, according to testimony.

The defense argued that Porter did not believe Gray was seriously injured until the van's final stop. His lawyers have said that Porter acted as any reasonable officer would have.

In contrast to the demonstrations in the days after Gray's death, the trial has drawn only a handful of protesters. On Wednesday about a half dozen were outside the courthouse, most from the People's Power Assembly, a local activist group.

Asked what she wanted from the Porter trial, demonstrator Julie MacGregor, 59, said: "He should be convicted and serve jail time." She was carrying a sign that read: "Jobs Not Police Killings."