RICHMOND, Va. (AP) -- Ten Virginia police officers have died in the line of duty this year, second only to California, officials said.

The men and women died either by gunfire or in traffic accidents; another suffered a heart attack during a training exercise, according to The Officer Down Memorial Page, a nonprofit organization dedicated to honoring America's fallen law enforcement officers.

"It's been a tragic year, but what we've experienced this year could happen to any state given the nature of the job," said John W. Marshall, Virginia's secretary of public safety. "I can't put any reason on it except that law enforcement officers have dangerous jobs, and danger is something officers are exposed to every day."

A total of 137 police officers were killed nationally this year, compared to 156 last year, according to the organization. In 2005, Virginia ranked in the middle with seven deaths while California topped the list with 18.

"It's a tremendous tragedy when you lose an officer," said Corinne Geller, spokeswoman for the Virginia State Police. "It's been a very difficult and tragic year for our members. We began and ended the year with an officer being killed in the line of duty."

Virginia State Trooper Kevin Manion died in February while helping another trooper with an accident in Clarke County. A rifle inside an overturned pickup truck discharged as the truck was being moved, striking Manion in the chest.

Last week, a West Virginia man acknowledged his role in Manion's death. David Ellis Ferrebee, 59, of Charles Town, W.Va., will be sentenced on Feb. 28 for involuntary manslaughter in Manion's death.

Nov. 24, Virginia State Police Trooper Robert A. Hill Sr., 42, was killed after an elderly driver hit him while he was talking to the driver of another car he'd pulled over for a traffic violation in Southampton County.

Officers from Chesterfield, Norfolk, Portsmouth, Virginia Beach, and Fairfax, Montgomery and Powhatan counties also were killed this year. Those killed were: Vicky O. Armel, 40; Gary J. Buro, 34; Seneca Darden, 25; Charles A. Fisher, 52; Michael E. Garbarino, 53; Robert E. Green, 33; Eric E. Sutphin, 40; William Tiedeman, 54.