The latest on the trial of a Baltimore police officer who is charged with manslaughter in the death of Freddie Gray, a 25-year-old black man who was injured in the back of a police transport van (all times local).

7:55 a.m.

Advocates are warning of a chilling effect on legitimate protests after Baltimore's schools chief sent a letter warning of consequences for violent response to a verdict of a police officer's trial in Freddie Gray's death.

Schools CEO Gregory Thornton said Monday that schools will facilitate student expression but warned of consequences for "walkouts, vandalism, civil disorder and any form of violence."

Activist group Baltimore Bloc said in a statement Tuesday that students won't allow their "voices to be stifled" and will issue a call to action if the justice system fails.

ACLU of Maryland Executive Director Susan Goering says students have a First Amendment and the letter could end up "chilling legitimate, peaceful protest activity."

Youth clergy and leaders plan the "Youth Stepping Up and Speaking Out" event Tuesday to urge expression "in decency and order" regardless of the verdict.

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4:30 a.m.

Prosecutors say it would have taken just two clicks for Officer William Porter to save Freddie Gray's life: one click to buckle the shackled man into a seatbelt in the back of the police transport van; another click to call into his police radio for an ambulance after Gray said he needed a medic.

But Porter's attorneys say he did more than enough for Gray on the day the detainee's neck was broken in the back of the van. They say Gray's death had nothing to do with the officer's actions.

A Baltimore jury on Monday began deliberating the fate of Porter, the first of six officers charged in Gray's death to stand trial. He's charged with manslaughter, assault, misconduct in office and reckless endangerment.

Deliberations continue Tuesday.