The protest march drew more than 1,000 people the evening of July 23.
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They gathered at the MacArthur BART station to demand justice for the fatal stabbing of 18-year-old Nia Wilson the day before.
VIDEO: 'Remember Her' A tribute to Nia Wilson
As the large crowd marched to downtown Oakland, police were there to facilitate the event and insure public safety.
Fights broke out on Broadway and officers converged to keep the peace.
Suddenly, someone threw an improvised explosive device into the police skirmish line.
SKY7's aerial footage shows the plume of smoke and the mayhem below.
VIDEO: This is the moment the BART stabbing suspect was arrested
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We were his target. Police officers were his target.
"He had stored in his backpack an explosive device," said Oakland Police Officers Association President Barry Donelan.
Ten officers were injured.
For three months, Oakland police with help from the FBI, tried to identify and track down the suspect.
RELATED: Here's how you can help the family of BART stabbing victim Nia Wilson
Lt. James Beere says it was difficult because he used street aliases and moved around a lot.
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But old fashioned police work, security camera footage and aerial's from ABC7's SKY7 helped investigators arrest Giovonni Gaines, who police say carried the bomb.
Beere, who was also injured in the bomb attack, headed the probe. He says security camera video also showed a juvenile accomplice.
"We saw Gaines pull up to the 13-year-old, remove an object from his backpack, hand that to 13-year-old, then light it," he said. "You see the 13-year-old throw it."
The juvenile was the first to be arrested.
Gaines was taken into custody and charged last week.
Go here for full coverage on the stabbing at Oakland's MacArthur BART station that took the life of 18-year-old Nia Wilson.