Gingrich, Romney, Santorum discuss Trayvon Martin

Updated: 5:44 p.m. ET

Republican presidential candidates Mitt Romney, Rick Santorum and Newt Gingrich have joined President Obama in weighing in on the shooting of Trayvon Martin.

After a rally in Shreveport, Louisiana on Friday, Romney called the murder a "terrible tragedy" that was "unnecessary, uncalled for, and inexplicable at this point."

He added that it was "entirely appropriate" for the district attorney to be looking into the matter, and to have called a grand jury investigation in the pursuit of justice.

"Our hearts go out to his family, his loved ones, his friends," Romney said. "This shouldn't have happened." He declined to comment on whether or not he felt the Justice Department should get involved.

Earlier in the day, the Romney campaign released a statement on the matter:  "What happened to Trayvon Martin is a tragedy," Romney said in the statement. "There needs to be a thorough investigation that reassures the public that justice is carried out with impartiality and integrity." Romney ignored a question on the Martin story three days ago.

Martin, who was 17 and African-American, was unarmed when he was shot by George Zimmerman in Sanford, Florida, nearly one month ago. Zimmerman maintains he shot the boy in self-defense after he followed Martin while he was serving on a neighborhood watch. He has not been arrested.

Gingrich discussed the situation on CNN Thursday night, where he said he believed the local district attorney was taking the right course.

"I have faith that the American system of justice and that this is why you have a balance between the police and the district attorney," he said. "The district attorney has the ability to step in and say, 'wait a minute, let's look at this again.' They're clearly doing that. The police chief himself has been suspended. And I think that Americans can recognize that while this is a tragedy -- and it is a tragedy -- that we are going to relentlessly seek justice and I think that's the right thing to do."

Gingrich was also asked Florida's Stand Your Ground law, which host Piers Morgan called "nonsense." Gingrich largely defended the law but suggested it did not apply in this case. People "should not be translating 'standing their own ground' into 'pushing somebody else,'" said Gingrich.

He added that "apparently the shooter was following the young man -- that's not a stand your own ground, that's a chase the other person into their ground." He said he expected that the law would thus not apply to this case, though he stressed he had not heard the full evidence in the case.

Speaking to reporters Friday, Gingrich hit many of the same notes about the situation. He said "there's a point in there where it ought to be some kind of signal that's pretty clear that this is a guy who found a hobby that's pretty dangerous."

"Do I think citizens ought to have the right to defend themselves if attack? Sure," he said. "The question here is was he attacked or was he the attacker and that's what the grand jury will lead to. If they decide he was the attacker I suspect they'll indict him and if they indict him their going to go to a jury trial. And I support that I think this is a case. Again if somebody breaks into your home and you're at risk you ought to have the right to defend yourself."

Santorum, like Gingrich, suggested the situation could be handled by local officials. The FBI, Justice Department and U.S. Attorney's office have said they will investigate the killing.

"I think that the local and state can do a great job here," Santorum said in Louisiana Friday, after firing at a shooting range. He added that "you already see the local community is reacting and responding and hopefully this matter will be an example of what law enforcement needs to do in a case like this."

"Stand Your Ground is not doing what this man did," Santorum said. "So, there's a difference between Stand Your Ground and doing what he did and it's a horrible case. It's chilling to hear what happened and of course the fact that law enforcement didn't immediately go after and prosecute this case is another chilling example of you know obviously horrible decisions made by people in this process."

On Friday, President Obama called the incident tragic, saying it is "it is absolutely imperative that we investigate every aspect of this and that everybody pulls together, federal, state and local, to figure out how this tragedy happened."

"You know, if I had a son, he'd look like Trayvon," Mr. Obama added.

Ron Paul's campaign has responded to an inquiry about whether Paul had a comment on the Trayvon Martin situation or on Mr. Obama's response to it. 

Sarah Boxer contributed to this report