Her son was killed on his 28th birthday in 2009. Carter's brother pulled the trigger. Her father shot himself soon afterward.
The horrifying family tragedy became one more private story in America's plague of gun violence. That year, 9,146 other people nationwide lost their lives in shootings.
The vast majority died in the type of daily gun violence that does not grab national headlines in the same way as the December massacre of 20 young children and six teachers at an elementary school in Connecticut, or the mass shooting last July in a Colorado movie theater that killed 12 people and wounded 70.
Those attacks became the focus of a bitter national debate over guns, which culminated with the defeat in the Senate of several proposals backed by President Barack Obama to tighten gun control laws, including banning military-style assault weapons and expanding background checks to stop criminals and the mentally ill from buying firearms.
Often lost in America's divisive gun control politics are the stories of people whose urban communities suffer the most from shootings every day. Although violent crime has been declining in the United States, it still far outstrips the rate of other developed countries. FBI figures show 8,583 people were killed by guns in 2011, the last year for which numbers were available.
That is nearly 24 people a day.
The figure is far higher when counting the number of people who kill themselves with guns. The federal Centers for Disease Control listed 19,392 gun suicides in the United States in 2010, the latest figures available.
Among the hard-hit places is Prince George's County, the Washington D.C. suburb where Stefan Carter was killed by his uncle 3 1/2 years ago. The county in the state of Maryland has long suffered under a reputation for violent crime, even though the U.S. Census Bureau lists it as the wealthiest majority African-American county in the country.
Support for gun control tends to run high in places like Prince George's County. In other parts of the country, particularly states with large rural populations, people say firearms are essential for hunting and personal safety, a right that has been protected by the Second Amendment of the Constitution for more than 200 years.
As the American frontier expanded westward, gun ownership became culturally entrenched, and for many citizens, it remains a way of life. But other Americans believe the Second Amendment, adopted in 1791, no longer makes sense in modern urban settings like Prince George's County, where shootings tear at society.
Florena Carter, a 24-year veteran police officer, has concerns about the easy access to handguns for civilians. She is convinced that simply owning a gun made her brother more likely to use it.
Her son and her brother had been out on the town celebrating Stefan's birthday. When they were heading home, she said, her son tried to stop her brother from driving because the older man was intoxicated. They fought and Carter's brother pulled a handgun and shot Stefan.
Carter was at a loss to explain how the dispute escalated. The two men had been close; neither was prone to violence, Carter said.
"All I can think is that it was the alcohol and that he had a gun," she said.
That argument goes counter to rhetoric often cited by U.S. gun advocates who say that gun restrictions can't stop people who are determined to misuse guns. What's more, they argue, such shootings among family members should not deny law-abiding citizens from owning guns for self-protection.
Since the Connecticut school shooting, many gun-rights activists have insisted the solution is for more people to own guns, not fewer. Politicians in some states have proposed laws allowing school teachers to carry guns, arguing that shooters will be less likely to target public places where they know people are armed. Supporters argue that restricting firearms rights will only prevent people from defending themselves from criminals who will find a way to get guns no matter what.
But in Prince George's County, Carter doesn't buy the argument that guns make people safer. Last year, she worked with a county program known as Gift Cards for Guns, which allows people to anonymously turn in their weapons in exchange for a $100 gift card.
Carter said she had not known her brother owned a handgun but was told by police that he had bought it legally.
Maryland recently passed a law that will make it tougher to buy such guns. One of the toughest gun control measures in the country, Maryland's law requires licensing, fingerprinting, and safety training to purchase a handgun, bans the sale of 45 types of assault weapons and limits ammunition magazine capacity to 10 rounds.
The National Rifle Association, the most powerful gun rights lobby in the country, is expected to challenge the Maryland statute in the courts, delaying its going into force.
Maryland is among several states that passed tougher gun control measures in response to the Connecticut school shooting, even as the push for stricter federal laws died in the Senate. Among them was Colorado, a state with a proud frontier tradition where gun ownership is common.
That has given hope to some advocates that gun control might be gaining ground despite fierce opposition by the deep-pocketed NRA, which spends heavily in U.S. elections. Although Republicans and a handful of Democrats in the Senate defeated the push for expanded background checks, polls at the time showed that about 90 percent of Americans favor such a measure.
Maryland has routinely had the 2nd highest homicide rate per 100,000 residents of all 50 states, despite also having the 5th highest per capita income. It had a gun deaths rate of 6.8 per 100,000 in 2011, more than 2 percentage points higher than the national average of 4.7 per 100,000.
That is due in large part to crime in Prince Georges County and the economically hard-hit city of Baltimore, according to the FBI and Census Bureau. Gun deaths have fallen dramatically in Prince Georges as the county government implements aggressive policies to build up the six most troubled neighborhoods, from programs to keep students in school to better street lighting, road repairs and demolition of abandoned buildings. The number of homicides has fallen from a high of 169 in 2005 to 64 last year.
Homicides are dropping similarly in other U.S. cities, prompting some to argue stricter gun measures are not needed to combat daily violence. But Prince Georges police chief Mark Magaw has welcomed Maryland's tough new gun law as a strong crime-fighting tool in his still-violent county.
So does Carter, who told her story at a gathering of other women coping with the loss of family members to gun violence. They have all been counseled by a group known as Community Advocates for Family and Youth.
Carter, now a board member of the organization, said she was still suffering despite sessions with police department psychologists when she found CAFY. Her husband had died of leukemia just five months before her son was killed.
"I thought, 'my God couldn't do that to me,'" she said.
Carter dabbed away tears as she recalled the early December morning 3 ½ years ago when the phone rang with the news of her son's death.
"My son was my only child. I don't have any grandchildren, and now I don't have hope of any," she said. "My son was two classes short of graduating with a dual degree."
In the passing weeks, Carter said she noticed that her father appeared increasingly depressed. She figured it was a natural reaction to the tragedy — until he killed himself.
Her brother will be out of prison in about two years, serving a sentence shortened because he accepted a plea deal. Carter doesn't know if she can forgive him.
"I love my brother. I've known him longer than my son. I changed his diapers," she said. But when he's released, "I just can't see us having a relationship."