Deadly Mass Shootings in 2019. (ABC News)(NEW YORK) -- The shooting at a Virginia Beach government office building was the deadliest mass shooting so far this year, but it certainly wasn't the first.

The Virginia Beach shooting was the 10th mass shooting in the first five months of 2019, marking a slight uptick in the number of incidents as compared to the same time period in 2018.

Even though there were more such incidents in the first five months of 2019 than in 2018 -- 10 compared to eight -- the number of fatalities was exactly the same: 51 victims killed.

The FBI defines a mass shooting as an incident in which four or more people, not including the suspect, are killed. While there is no publicly accessible federal tracker of such incidents, various groups and watchdog organizations keep their own lists, often using different criteria for what qualifies as a mass shooting.

For the list compiled by ABC News below, the incidents took place over the course of a day and involved four or more victims, not including the suspect. For instance, shooting sprees that spanned longer amounts of time were not included on this list.

Here is the list of mass shootings in the U.S. so far in 2019.

1. Jan. 23: Shooting at a Florida bank, 5 victims

Five people were killed when a gunman opened fire in a SunTrust Bank in Sebring, Fla., police said.

The 21-year-old suspect, Zephan Xaver, barricaded himself inside before later surrendering to authorities, police said.

"I have shot five people," Xaver allegedly told 911 dispatchers, according to a joint statement released by the Highland County Sheriff's Office and Sebring Police Department.

Xaver had been hired by Avon Park Correctional Institution on Nov. 2 and was training to be a correctional officer when he resigned on Jan. 9, according to the Florida Department of Corrections. Xaver had no disciplinary incidents while employed with the department.

2. Jan. 24: Shooting in Georgia before suspect flees the state, 4 victims

After allegedly shooting three people at two scenes in Rockmart, Ga., a suspect was later found and taken into custody in Indiana.

At the first scene, 27-year-old suspect Daylon Delon Gamble allegedly shot three people, two of whom died, and then went to another scene and shot and killed two others, according to the Georgia Bureau of Investigations.

3. Jan. 26: Domestic violence incident in Louisiana, 5 victims

An "armed and dangerous" 21-year-old man from Louisiana who allegedly fatally shot his parents, girlfriend, her father and her brother, was captured outside his grandmother's house in Virginia, authorities said.

Dakota Theriot was wanted on multiple counts of first-degree murder, home invasion and weapons charges stemming from a killing spree that began in Livingston Parish, La. -- just east of the state capital, Baton Rouge -- and continued at his parents' trailer in Ascension Parish.

"He was very sleep deprived," Richmond County Sheriff Steve Smith told ABC News. "Once put in our booking room, he went straight to sleep... he seemed a little disoriented."

4. Feb. 3: Palm Springs, 4 victims

A suspect was apprehended days after the shooting deaths of three teenagers and a man in the Palm Springs area.

The Desert Sun newspaper published a timeline surrounding the shootings, which states that at least two of the victims had been talking about a robbery plot earlier in the day of the shooting, and then they and a friend were found dead later at a trail, with the 4th victim found later on that day.

5. Feb. 11: Domestic incident involving a child victim in Texas, 4 victims

A 15-month-old girl, the child’s parents and the child’s grandparents were all found dead on a property in Polk County.

“This is a horrible, horrific scene – a horrible, horrific crime,” Polk County Sheriff's Office Chief Deputy Byron Lyons said in a news conference at the time, as ABC affiliate KTRK reported.

The toddler, Ranley Horn, was found outside near her mother Ashley Horn, 27, and Ashley’s grandmother, Linda Delaney, 72.

Inside the home, investigators found Linda’s husband Carlos Danley, 74, and Randy Horn, 54, who is also a relative.

No suspect was ever arrested, though the sheriff’s office confirmed that they are not actively looking for a suspect, implying but not directly stating that the case was considered a murder-suicide. It is not immediately clear and has not been released publicly who investigators believe was the suspect in the shooting.

6. Feb. 15: Shooting at a manufacturing plant in Illinois, 5 victims

Five victims were killed and five police officers were injured by gunfire in Aurora, Ill., when an apparently disgruntled employee at an industrial warehouse opened fire after being told he was being fired from the job where he had worked for 15 years, according to authorities.

The gunman, identified as Gary Martin, 45, was killed by responding police officers, according to Aurora Police Chief Kristen Ziman.

The shooting unfolded at the Henry Pratt Company in Aurora, a town about 40 miles west of Chicago.

7. Feb. 16: Hostage situation turns deadly, 4 victims

When police entered a home in Clinton, Miss., police found four dead victims and the suspect, Nam Le, wounded. The suspect later died after being transported to a local hospital.

Le fired upon officers when they arrived at the home, leading to a standoff.

8. April 28: Shooting in Ohio, 4 victims

Four relatives were found shot dead inside an apartment in West Chester, Ohio. The investigation into the shooting is ongoing, but police have told local reporters that it is being classified as a homicide.

The victims were identified by police as the apartment owners Hakiakat Singh Pannag, 59, his wife Parmjit Kaur, 62, their daughter Shalinderkit Kaur, 39, and Parmjit Kaur’s sister Amarjit Kaur, 58, according to The Journal-News.

Police responded to the scene after receiving a call from Shalinderkit Kaur’s husband, Gurpeet Singh, who called 911 after finding the bloody scene, according to The Cincinnati Enquirer.

9. May 13: Shooting in Missouri, 4 victims

A brawl inside a St. Louis home reportedly led to a gun battle where five victims in their 20s and 30s were shot, according to the St. Louis Post-Dispatch.

Of those, three victims were found dead at the scene and the fourth died later as a result of their injuries, the newspaper reported.

Initial reports suggested that the four deceased men were related.

The home where the shooting occurred is reportedly in a part of town called Hayden's Rectangle, which the newspaper said is an area that has been the focus of crime fighting efforts in the past.

10. May 31: Workplace shooting in Virginia Beach, 12 victims

The shooting at a municipal building in Virginia Beach was the deadliest of the year in 2019, with 12 victims meeting their end.

The specific motive of the suspect, who was believed to be a disgruntled employee, remains unknown at this time as police continue to investigate the shooting.

The suspect, DeWayne Craddock, allegedly used two .45-caliber pistols in the rampage and law enforcement officials reported that both guns were purchased legally by the suspect.

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