(CNN) Gunfire claimed the lives of at least five on-duty officers in an unusually deadly week for U.S. law enforcement.

In four days, five officers were killed in the line of duty in shootings around the country, more than doubling the number of officers who have died by gunfire so far this year.

A Colorado sheriff's deputy died after being shot Monday; two sheriff's deputies were killed Wednesday in Maryland; a police officer in Georgia is dead after gunfire broke out Thursday while he and other officers were serving a warrant; and a police officer shot Wednesday night in North Dakota did not survive, authorities say.

Before these deaths were reported, the National Law Enforcement Officers Memorial Fund said at least three other U.S. law enforcement officers had died from gunfire in the line of duty this year. Adding the totals together, that would make at least eight since January 1.

One officer was shot to death during the same period last year, and at least 42 were fatally shot in 2015 -- a rate of less than one per week -- according to the group.

At least 124 officers died in the line of duty last year -- more than two per week -- from all causes, the group said.

Below are details of this week's shootings:

2 sheriff's deputies killed in Maryland

A gunman shot and killed two deputies Wednesday at a restaurant and outside a nearby apartment complex in eastern Maryland after the officers were called to investigate him, authorities say.

Officers went to a Panera Bread restaurant in Abingdon for an investigation late Wednesday morning, according to the Harford County Sheriff's Office. Senior Deputy Patrick Dailey tried to talk to the man, but the man shot Dailey in the head, Sheriff Jeffrey Gahler said.

After the gunman fled toward nearby apartments, Senior Deputy Mark Logsdon saw the man sitting in a vehicle near the complex, and the gunman shot and killed Logsdon, police said. Other deputies fired at the gunman, who was pronounced dead at the scene.

"It's absolutely devastating to the people who wear this uniform," Gahler said Thursday. "These men are heroes. ... They served this county ... honorably."

Dailey was a 30-year veteran of the agency; Logsdon had served 16 years.

Police said the gunman was David Bryant Evans, 67. Gahler said he didn't immediately know why a tipster had asked police to check on Evans, but he added his deputies knew the man was wanted on a warrant out of Florida over an alleged assault of a police officer.

Gahler said he believed Evans shot the first deputy because the gunman knew about the warrant and didn't want to be arrested.

Colorado deputy dies days after shooting

Also Wednesday, Colorado authorities announced the death of a sheriff's deputy shot in the line of duty two days earlier.

Mesa County sheriff's Deputy Derek Geer was shot Monday morning as he tried to detain a man in Grand Junction, authorities said. Greer had responded to a report of a suspicious person with a gun near railroad tracks south of the Interstate 70 business loop, police said.

Geer saw someone matching the person's description and tried to detain him, but the person shot him, police said.

Authorities said they later arrested a teen they believe shot Geer: Austin Patrick Holzer, 17, of Grand Junction. Holzer was held initially on charges of attempted second-degree murder and possession of a weapon by a previous offender.

Fargo police officer shot during home standoff

A Fargo, North Dakota, police officer was shot during a standoff at a home there Wednesday night, police said.

Officer Jason Moszer did not survive, according to police Deputy Chief Joe Anderson.

Moszer was shot after he and other officers went to a Fargo home to investigate a report of a domestic disturbance, police said.

The standoff ended when a suspect was found dead, apparently of gunshot wounds, CNN affiliate WDAY-TV reported , citing police. WDAY said it wasn't immediately clear who shot the suspect.

Georgia officer killed while serving warrant

A Georgia police officer was shot and killed Thursday morning after gunfire broke out while he and other officers were attempting to serve a drug warrant, said Clayton County police Sgt. Ashanti Marbury.

When officers entered an apartment in Riverdale while serving a "no knock" warrant, one man ran out the back door, Marbury said.

While trying to get away, the suspect encountered a police officer and shot him. The suspect continued to run until he encountered another officer, who shot him.

Both the suspect and the officer were taken to the hospital. The officer died; the suspect survived, Marbury said.

Neither the name of the officer nor the suspect has been released.

The Georgia Bureau of Investigation is investigating.

California deputy, civilian pilot killed in plane crash

Besides this week's gunfire deaths, a California sheriff's deputy and a civilian pilot were killed Wednesday afternoon when the plane they'd been using to help officers on the ground with an arrest crashed near a road in Tulare County.

Tulare County Sheriff's Deputy Scott Ballantyne, 52, and pilot James Julio Chavez, 45, died when the two-seater plane went down about 65 miles southeast of Fresno.

The plane was being used to help deputies on the ground locate suspects, the Tulare County Sheriff's Office said. The duo had just completed a mission in which deputies detained a person who'd brandished a weapon, the office said.

The cause of the crash wasn't immediately known. Federal transportation authorities will investigate, the sheriff's office said.