WASHINGTON >> President Barack Obama spoke in unusually personal terms Friday about the shooting death of an unarmed black teenager in Florida, a case that has roiled civil rights activists and a suburban Orlando community. "If I had a son, he’d look like Trayvon," Obama said, vowing to "get to the bottom of what happened."

Obama expressed sympathy for the parents of 17-year-old Trayvon Martin, who was shot on Feb. 26 in Sanford, Fla., a suburb of Orlando, by a neighborhood watch volunteer who said he was acting in self-defense.

"I can only imagine what these parents are going through, and when I think about this boy, I think about my own kids," Obama said, calling the case a "tragedy."

The nation’s first black president aimed his message at Martin’s parents, saying, "If I had a son, he’d look like Trayvon. I think they are right to expect that all of us as Americans take this with the seriousness that it deserves, and we’re going to get to the bottom of what happened."

Obama said that "every parent in America should be able to understand why it is absolutely imperative that we investigate every aspect of this and everybody pulls together, federal state and local, to figure out exactly how this tragedy happened."

Martin’s parents, Tracy Martin and Sybrina Fulton, thanked Obama for his support, saying in a statement the president’s words "touched us deeply and made us wonder: If his son looked like Trayvon and wore a hoodie, would he be suspicious too?"

Obama brought his voice to an issue that is sensitive in Florida, a large and diverse state that plays an influential role in presidential elections. The Orlando area in central Florida is particularly important, acting as a bellwether for statewide elections.

Republican presidential candidates weighed in after Obama spoke. Former Pennsylvania Sen. Rick Santorum called the shooting "horrible case" and referred to Florida’s "stand your ground" law, which gives people wide latitude to use deadly force rather than retreat during a fight.

Santorum said: "Stand your ground is not doing what this man did."

Former Massachusetts Gov. Mitt Romney issued a statement after Obama spoke that read: "What happened to Trayvon Martin is a tragedy. There needs to be a thorough investigation that reassures the public that justice is carried out with impartiality and integrity."

The Justice Department and FBI have opened a civil rights investigation, and a grand jury is considering whether to charge George Zimmerman, who acknowledged shooting the teen but said it was in self-defense. Martin’s parents, civil rights activists and others who have rallied to the cause say they won’t be satisfied until Zimmerman is arrested.

Police Chief Bill Lee stepped down temporarily this week to try to cool the building anger that his department had not arrested Zimmerman. Hours later, Gov. Rick Scott announced that the local state attorney, Norman Wolfinger, had recused himself from the case in hopes of "toning down the rhetoric" surrounding it.

Martin was returning from a trip to a convenience store when Zimmerman started following him, telling police dispatchers he looked suspicious. At some point, the two got into a fight, and Zimmerman pulled out his gun.

Zimmerman told police Martin attacked him after he had given up on chasing the teenager and was returning to his sport utility vehicle.

Obama cautioned before speaking that he must "be careful so we’re not impairing any investigation." But he said he was glad the Justice Department was investigating and that Florida officials had formed the task force.

"I think all of us have to do some soul searching to figure out how did something like this happen, and that means we examine the laws and the context for what happened as well as the specifics of the incident," Obama said.

The case resonates with many black Americans, a key voting group during Obama’s 2008 election, who see it as yet another example of bias toward blacks. Civil rights groups have held rallies in Florida and New York, saying the shooting was unjustified. Of Sanford’s 53,000 residents, 57 percent are white and 30 percent are black.

At a rally in Sanford on Thursday night, protesters including civil rights leader Al Sharpton called for Zimmerman to be prosecuted.

"We cannot allow a precedent when a man can just kill one of us … and then walk out with the murder weapon," said Sharpton, flanked by Martin’s parents and a stage full of supporters.

Obama has tried to downplay race, as he did early in his term after the controversial arrest of Henry Louis Gates Jr., a black Harvard University professor, by a white police sergeant in Cambridge, Mass.

Gates was arrested in his own home after the police sergeant arrived to investigate a possible burglary. The charges were dropped, but Obama said the police had "acted stupidly," breathing life into a lingering debate. The president said later he should have expressed his concerns with different language and invited both Gates and Sgt. James Crowley to the White House for a beer.