(CNN) -- The saga of Trayvon Martin continued to energize thousands around the country Monday, spurring demonstrations across the United States and even turning what had been a regularly scheduled city commission meeting into a hot-ticket event.
Exactly one month ago, the 17-year-old was shot dead in Sanford, Florida, while heading back from a convenience store, where he'd picked up a bag of Skittles and an iced tea.
The teen's admitted shooter, neighborhood watch volunteer George Zimmerman, hasn't been charged in the case, and his lawyer has said his client shot Martin in self-defense.
Yet the young victim's parents, as well as their supporters, have suggested that the shooter thought their son was "suspicious" because he was black, adding that they feel local police bungled the case in numerous ways -- chief among them, by not arresting Zimmerman.
"Do the right thing, arrest Zimmerman now," said the Rev. Al Sharpton, in presenting Sanford's city commission with a petition he claimed had been signed by 2 million people who urged that the shooter be detained.
Sharpton joined Trayvon Martin's parents at a trio of well-attended events Monday in the central Florida city.
The first was a noontime "town hall" forum hosted by Roland Martin, a CNN contributor. After that, the parents spoke out forcefully in response to recently reported news that February 26 -- the day of the shooting -- their son wasn't in school because he'd been suspended for 10 days after an empty plastic bag found in his book bag had marijuana residue. Family spokesman Ryan Julison confirmed the suspension.
"The only comment that I have right now is that they've killed my son and now they're trying to kill his reputation," Trayvon Martin's mother, Sybrina Fulton, said at a news conference following that forum.
The day's most anticipated event was initially expected to be a standard city commission meeting. But in response to the public outcry -- and criticisms over the Sanford Police Department's handling of the case -- city officials decided to focus the meeting on the incident.
Some waited in line for several hours for the chance to get one of 500 available seats in the Sanford Civic Center. The meeting had been moved to there to accommodate a large crowd, but even then many hundreds weren't able to get into the packed hall.
"I just want to reaffirm that we truly are in pursuit of truth and justice, and we've looked outside our walls (for help)," Sanford Mayor Jeff Triplett said, referring to the city's outreach to the U.S. Justice Department, the FBI and others to review how the case was and should be handled. "And we will take swift and decisive action," Triplett added.
Over the next several hours, several speakers allied with the Martin family took to the lectern demanding Zimmerman's arrest, calling for city officials to take a stand, and criticizing how the police investigation was handled.
"We're not asking for an eye for an eye, we're asking for justice, justice, justice," said Tracy Martin, Trayvon's father.
The parents eventually left and headed to a nearby park -- where the city commission meeting had been broadcast on large video screens -- for a rally scheduled for later in the day.
The family had plenty of support Monday, and not just in Sanford.
In communities big and small, people wore hooded sweatshirts -- hoodies -- and carried Skittles and iced tea -- just as Martin had done on the night of his death -- as they called for Zimmerman's arrest, legislative changes and an end to racial profiling.
They included throngs of people who marched on streets in front of the Georgia State Capitol in Atlanta, decrying a "stand your ground" law in that state -- as in Florida -- that allows people to use force in self-defense.
More than 2,100 miles away in San Francisco, others held up signs reading, "We demand justice."
Similar scenes played out in Iowa City, Iowa; Houston; Detroit; Philadelphia; and places in between.
In Washington, speakers organized by the National Black United Front lined up, one by one, to grab a bullhorn and demand a "conviction" of Zimmerman. When protesters agreed with a speaker, they shook their bags of Skittles.
Demonstrators there said they believed race was a factor in Martin's death at the hands of Zimmerman, who is a white Hispanic.
"If this had been a brother, he'd be on death row!" one protester shouted, referring to Zimmerman.
Maria Roach, an African-American mother of a 7-year-old boy, delivered to the U.S. Justice Department a printout copy of an online petition with over 500,000 digital signatures to demand that agency take action.
"We want a conviction, we want an arrest, and we want it now," Roach said.
CNN's Eric Marrapodi and Vivian Kuo contributed to this report.