12 recent mass shootings that gained national attention

At least six people were killed and several others injured after a gunman opened fire in a Walmart in Virginia on Tuesday, police said.

The incident is one of more than 600 mass shootings reported so far this year by the Gun Violence Archive, which defines a mass shooting as four or more victims shot or killed.

While mass shootings are an anomaly when it comes to gun violence in America, this year has been rocked by horrific incidents, including several that unfolded in public, such as shootouts between multiple gunmen, targeted attacks or active shooter events. They cut the lives short of victims young and old, while injuring and scarring countless survivors, sent whole communities into mourning and sparked repeated calls for gun reform. Many incidents also remain unresolved, with investigations underway or court proceedings ongoing.

Here's a look at 12 mass shootings that gained national attention this year.

March 19: Car show in Dumas, Arkansas

Twenty-six people were wounded, including five children ranging in age from 19 months to 11 years old, and a 23-year-old man killed after gunfire "swept across a crowd" while attending a car show in rural Arkansas, state police said. One person, who allegedly returned gunfire after getting struck in a shootout, was arrested and charged with first-degree battery and aggravated assault, according to court documents.

April 3: Epic Easter Bike Out & Field Party in Dallas, Texas

An event billed as a family-fun trail ride and outdoor concert turned deadly, when one person fired into the air and a second person fired in the crowd's direction, police said. A 26-year-old man was killed and 16 others, including three juveniles, were injured by gunfire. Two men were arrested and charged with felony deadly conduct in the days after the shooting.

April 3: Entertainment district in Sacramento, California

Six people were killed and 12 wounded after gunfire erupted in downtown Sacramento, just blocks from the state Capitol building, in a gunfight between multiple gang rivals, police said. The victims killed ranged in age from 21 to 57. Three alleged gang members were charged with multiple counts of murder stemming from the mass shooting.

April 12: Subway in New York City

A gunman opened fire on a crowded subway car during the morning commute, as the train approached the 36th Street subway station in Brooklyn's Sunset Park neighborhood. A man witnessed mumbling to himself on the subway car, donned a gas mask and detonated a smoke canister before pulling out a handgun and firing a barrage of 33 bullets, hitting 10 people, a police official told ABC News. The suspect was arrested more than 24 hours into an intense manhunt and has pleaded not guilty to charges of conducting a terror attack against a mass transportation system and discharging a firearm during a crime of violence.

May 14: Tops supermarket in Buffalo, New York

Ten Black people were killed and in what authorities said was a racially motivated attack at the Tops grocery store. The 19-year-old suspect, who faces state and federal hate crime charges, has pleaded not guilty during arraignments in state and federal court. A change of plea hearing for the suspect was adjourned this week with no new date immediately set, as Buffalo Mayor Byron Brown appeared to confirm recent reports that the suspect is expected to plead guilty to the state charges. The indictment was the first in the state to invoke a statute that comingled terrorism and hate crimes.

May 24: Robb Elementary School in Uvalde, Texas

In one of the deadliest mass shootings in recent U.S. history, 19 children and two teachers were killed after a gunman opened fire with an AR-15-style rifle inside an elementary school classroom. 17 people also suffered non-life-threatening injuries. The 18-year-old gunman was killed by law enforcement 77 minutes after entering the school, authorities said. The tragedy has been intensely criticized over the failures that resulted in the delayed law enforcement response.

June 1: Saint Francis Hospital in Tulsa, Oklahoma

A suspect targeting an orthopedic surgeon who recently performed back surgery on him killed four people, including the doctor, at the Natalie Building at Saint Francis Hospital before dying from an apparent self-inflicted gunshot wound, police said. In a letter recovered at the scene, the suspect blamed the doctor for "ongoing pain following the surgery," police said. Multiple people were also injured in the shooting.

July 4: Fourth of July parade in Highland Park, Illinois

Seven people were killed and more than 30 injured after a gunman opened fire from a rooftop above the crowd attending the Fourth of July celebration in the Chicago suburb. Those killed included the parents of a 2-year-old who survived the shooting. The wounded ranged in age from 8 to their 80s, authorities said. The accused 21-year-old gunman has pleaded not guilty to 117 charges, including 21 counts of first-degree murder (three counts for each victim). Investigators have not commented on a possible motive.

Oct. 13: Nature trail in Raleigh, North Carolina

A teenager is alleged to have killed five people, including his older brother, and injured two others in a mass shooting that spanned 2 miles. A dog belonging to one of the victims was also shot and killed, police said. The 15-year-old suspect was taken into custody with life-threatening injuries. Raleigh police have not said if the suspect was shot by officers or himself, and a motive remains under investigation.

Nov. 13: University of Virginia in Charlottesville, Virginia

A class field trip turned tragic when a gunman opened fire on a bus full of students returning home from seeing a play in Washington, D.C., university officials said. Three football players were killed and two other students were injured in the shooting. The suspect, a former member of the school's football team, was taken into custody following an overnight manhunt and faces multiple charges, including three counts of second-degree murder. A motive has not been released.

Nov. 19: Club Q in Colorado Springs, Colorado

Five people were killed and 17 suffered gunshot wounds after a shooter armed with a long gun opened fire in the LGBTQ nightclub, police said. Two patrons confronted and fought with the shooter, preventing more victims, police said. The suspect in the shooting has yet to be formally charged, though is being held in jail without bond on 10 "arrest only" charges: five counts of first-degree murder and five counts of committing a bias-motivated crime causing bodily injury, online court records show.

Nov. 22: Walmart in Chesapeake, Virginia

A Walmart employee armed with a handgun and multiple magazines shot and killed six people, including a 16-year-old, and wounded three others after opening fire in a break room, police and officials said. The suspect died at the scene from an apparent self-inflicted gunshot wound, police said. He had been an employee since 2010, Walmart said. A motive remains unknown at this time.