Police officers respond to a barricaded suspect situation following a stabbing and shooting incident in Sunset, La., on Aug. 26. (Leslie Westbrook/The Advocate via Reuters)

On Wednesday, a Louisiana police officer named Henry Nelson was shot and killed after responding to a report of a domestic dispute. Nelson is the 22nd police officer shot and killed by a suspect so far this year, but he is the second law enforcement officer killed in Louisiana this week. Steven Vincent, a senior trooper with the Louisiana State Police, had approached a man inside a truck that was in a ditch Sunday afternoon when the man shot Vincent in the head, police said. Vincent died the following morning.

All told, five of the 22 officers shot and killed by suspects were slain in Louisiana, more than any other state, according to the Officer Down Memorial Page, a nonprofit organization that tracks line-of-duty fatalities.

Overall, if you expand the number of fallen officers so far this year to include those who died in other circumstances (which includes traffic accidents and heart attacks), Louisiana has lost nine officers, tied with Texas for the most so far this year, according to records kept by the National Law Enforcement Officers Memorial Fund, a nonprofit in Washington that studies officer fatalities. This is despite Texas having more than five times as many residents as Louisiana and more than three times as many law enforcement personnel capable of making arrests. (Only California and New York have more sworn law enforcement personnel than Texas, Justice Department figures show.)

[“He loved life:" La. police officer fatally shot after responding to call]

These deaths in Louisiana have been attributed to a range of situations, highlighting what current and former police officers interviewed this year called the unpredictable nature of their jobs.

Nelson was fatally shot with his own firearm after responding to a domestic incident, authorities said. Vincent was killed while checking on a vehicle that was stuck in a ditch. Thomas LaValley, a Shreveport officer, was called to a house Aug. 5 about an armed man threatening someone inside. When he arrived, police said, the man shot LaValley multiple times. A manhunt ensued, and the following day, police arrested Grover D. Cannon, 27. 

In June, Daryl Holloway, a New Orleans police officer, was shot and killed by a man he was taking to a city jail, authorities said. Travis Boys, 33, was arrested after a two-day manhunt. A month earlier, James Bennett Jr., an officer with the Housing Authority of New Orleans, was found shot to death in his car the morning after he was guarding a construction site; police have not publicly identified any motive or suspects thus far.

The deaths share little other than the basic facts: Officers in the course of routine police work, responding to calls or traffic incidents, were gunned down on the job.

Overall, more officers have died this year than last year, but that is due to an increase in traffic accidents, according to data from the National Law Enforcement Officers Memorial Fund. Fewer officers have been shot and killed so far this year than last year. And statistics suggest being a police officer has gotten much safer over the years, as about 50 police officers were fatally shot each year over the past decade, a number that has dropped by more than half since the 1970s.

Still, in interviews this year, police officers and their relatives have said they feel under siege amid protests focused on how police use force. Some have said they are more cautious, while others expressed worries about the level of anger focused at them. And still others worry about how the number of law enforcement officers shot and killed was much higher in 2014 than in 2013, an uptick that came after a year with the fewest officers killed since 1980.

“The risk is always there,” Baltimore County Police Chief Jim Johnson, chairman of the National Law Enforcement Partnership to Prevent Gun Violence, said in an interview earlier this summer.

Johnson said he believes there is a heightened danger to police officers, and said some of that comes from the sheer volume of guns on the streets. He also said additional danger comes from people who commit violent crimes and don’t want to be arrested, as well as groups that are opposed to the government and could become violent.

While the number of officers killed has declined, this tally would “be much higher” if not for improvements in the protective gear worn by officers and advances in the medical and trauma care they can receive after shootings, Johnson said.

While police officers have the legal right to use force when needed, most civilians don’t except in cases of self-defense, according to David A. Harris, a law professor at the University of Pittsburgh and an expert in police use of force. Killing a law enforcement officer is often an aggravating factor that can warrant the death penalty in federal cases and numerous states.

“The entire justice system is, in a way, the victim when a police officer is killed,” Harris said. “So a person who kills a police officer in the course of that police officer doing his or her duty [is] committing an assault against all of the forces of law and order.”

Both of the men accused of killing Louisiana officers this week were taken into custody. Kevin Daigle, 53, has been charged with murdering Vincent, the state trooper, as well as another man. On Thursday, authorities charged Harrison Lee Riley Jr., 35, with first-degree murder. Police say that in addition to shooting Nelson, Riley stabbed three women, one of whom died.

Related:

Fewer police officers shot and killed over first half of 2015 than 2014

Officers describe increased tension amid protest movement

The FBI released some details on the officers who were killed last year

Authorities say Henry Nelson, a small-town south Louisiana police officer, was killed with his own gun while trying to calm a domestic dispute. The suspected killer was his cousin, Harrison Lee Riley Jr. (AP)