Two Gwinnett County men have been charged with involuntarily manslaughter for allegedly firing a gunshot that killed a neighbor seconds before the new year.

Two minutes before midnight Friday, Sergio Martinez and his relatives turned down the music and prepared to welcome in the new year according to their custom, with a family hug.

Martinez didn't make it that long.

Out of nowhere, a bullet pierced the curtain in the living room of the home on Worcester Place near Lilburn. Seconds later, another projectile crashed through the ceiling of the kitchen, where Martinez and several children were watching a neighbor's fireworks through a sliding-glass door.

The bullet struck Martinez in the head. The 34-year-old lay dead on the kitchen floor when police arrived shortly after midnight.

Police say the cause was one of several instances of celebratory gunfire that occurred in metro Atlanta over the holiday.

"It all happened so quick," Martinez's niece Marlen Martinez, 24, said Monday as she fought back tears. "Every year, everywhere they shoot. It's not the first year we heard them. This time, I guess, it just got us."

Marlen Martinez said her uncle, who never married or had children, lived with her family at the home for six years. The native of Mexico worked hard installing marble and granite countertops.

"We know it was an accident," Marlen Martinez said. "We know everybody shoots at this time of year. We're against it, obviously. But we don't have any hate against anybody."

Monday evening, police announced the arrest of a stepfather and stepson who live across the street from the Martinez family. Ervin Turner, 62, and Jesse Foster, 20, have each been charged with involuntary manslaughter, Cpl. Jake Smith said. Turner and Foster were both taken into custody without incident, Smith said.

"They both have admitted they did, in fact, fire the gun," Smith said.

Investigators have not determined which man fired the fatal shot, Smith said. But both were apparently firing a single gun to celebrate the new year, he said.

Celebratory gunfire has been a problem year after year in metro Atlanta despite police and community attempts to quell it.

Between 9 p.m. Friday and 6 a.m. Saturday, Gwinnett County received 75 calls to 911 reporting shots fired. Gwinnett police also arrested a 16-year-old in Loganville they said pulled the trigger on a gun borrowed from someone. The teen was charged with reckless conduct and possession of a pistol without a license, both misdemeanors, and cited for a county ordinance that makes it unlawful to fire a weapon within 500 feet of a roadway.

Atlanta police also arrested two people Friday night on allegations they fired into the air. Benny Lee Riggins was arrested shortly before 11 p.m. on Etheridge Court in northwest Atlanta. Riggins, 25, was charged with reckless conduct. Earlier Friday, Manvel A. Britton was arrested on Laurel Avenue after a 911 caller reported shots fired.

Cobb County had 30 calls to 911 regarding shots being fired throughout the course of the evening.

Sgt. Dana Pierce, a spokesman for the Cobb County Police Department, said celebratory gunfire happens "virtually nonstop" around the county on both New Year's Eve and the Fourth of July.

Pierce said people should know better because information about Georgia's gun laws is easily accessible on the Internet.

"People will tell you they didn't know because they don't want to get in trouble, but the reality is people will probably push the limit and do it anyway," Pierce said.

On New Year's Day 2010, 4-year-old Marquel Peters was killed when a bullet fired into the air in DeKalb County came down through the roof of the Church of God of Prophecy on Covington Drive.

Peters' death galvanized the DeKalb community to collect pledges, called "Marquel's Pledge," from more than 1,000 individuals who promised not to fire weapons during holiday revelry. Seven gun shop owners in DeKalb also pledged to restrict or suspend the sale of ammunition two days before the Fourth of July and New Years Eve in hopes of preventing a similar death.

One state lawmaker is calling for harsher punishment of trigger-happy carousers.

Last week, state Sen. Gloria Butler, D-Stone Mountain, introduced a resolution in the Senate to raise awareness about celebratory gunfire. The resolution asks state lawmakers to study and adopt tougher criminal penalties for those who cause injury or death.

Staff writer Alexis Stevens contributed to this article.