At least 28 people are reported dead after an elementary school shooting rampage.
The tragedy, the worst since the Virginia Tech massacre in 2007, is one of a spate of deadly mass shootings in America this year.
The violence has spurred discussions about gun laws and mental healthcare.
Here's a timeline of some of the worst deadly shootings in the U.S. this year:
February 21, 2012: Jeong Soo Paek burst into a spa his family owned in Norcross, near Atlanta, Ga. He killed four relatives before turning the gun on himself, the Atlanta Journal-Constitution reported at the time. Police speculated that financial problems motivated the shooting.
February 27, 2012: A 17-year-old student, T.J. Lane, confessed to going into his Chardon, Ohio high school cafeteria and shooting students at random. Three students died and two were hospitalized, The New York Times reported. Lane said he stole the gun from a relative who had obtained it legally.
March 30, 2012: A gunman drove by and opened fire on a crowd of mourners outside a funeral home in Miami, Fla. Two people died and 12 more were injured, the Miami Herald reported. The mourners were gathered for the funeral of 21-year-old Marvin Andre, who also died in a shooting.
April 2, 2012: One L. Goh opened fire at Oikos University in Oakland, California. He killed seven people and injured at least three more. Goh was a former student at the school and was said to be angry that he was expelled for poor behavior, CNN reported.
April 6, 2012: Five African-American men were gunned down in separate incidents in Tulsa, Oklahoma, ABC reported. Police arrested Jake England, 19, and Alvin Watts, 32, and said that the murders were motivated by racism. Three men died and two were seriously injured.
May 29, 2012: Ian Stawicki went to a cafe in Seattle's University district, shooting and killing four people, ABC reported at the time. He then fled to a parking lot and shot another woman before killing himself. He wasn't thought to have known his victims.
July 20, 2012: James Holmes, 24, allegedly broke into a midnight premiere of "The Dark Knight Rises" in Aurora, Colo., killing 12 people and injuring roughly 60 more. Later, police revealed that Holmes, a doctoral student in neuroscience, spent $20,000 on ammunition and weapons.
August 5, 2012: Seven people died after gunfire broke out at a Sikh temple in Oak Creek, Wisconsin. The gunman, identified by police as Wade Michael Page, also died in the shooting. He was a white supremacist and the shootings were said to be racially motivated.
August 13, 2012: Three people including a police officer were killed in shootings near the campus of Texas A&M University. The alleged shooter, Thomas Caffell, was said to be obsessed with video games and was having financial problems.
August 24, 2012: Jeffrey Johnson shot a former coworker and injured nine more people before being shot and killed by police. The shooting occurred near New York's Empire State Building during rush hour.
August 28, 2012: Robert Gladden Jr., 15, allegedly brought a gun to Baltimore's Perry Hall High School and shot a fellow student, resulting in a critical injury. The boy's mom said he had been bullied.
August 31, 2012: Ex-Marine Terrell Tyler, 22, opened fire at the Old Bridge, New Jersey supermarket where he worked. He killed two of his coworkers before shooting himself in the head.
September 28, 2012: Andrew Engeldinge walked into his former office, Accent Signage Systems in Minneapolis, and "carefully selected" coworkers to execute. He fatally shot five people before turning the gun on himself.
October 21, 2012: Radcliffe Haughton, 45, bought a handgun and drove to a Milwaukee, Wisconsin, spa where his estranged wife was working. He killed three people, including his wife, before shooting himself.
November 6, 2012: Lawrence Jones, 42, opened fire at Valley Protein, the Fresno, California meat-processing plant where he worked. He killed two people and himself. Two more were seriously injured.
December 12, 2012: Jacob Tyler Roberts, 22, allegedly stole a rifle from a family friend and went into a Clackamas, Oregon shopping mall with "several fully-loaded magazines" of ammunition. He killed two bystanders before shooting himself.
December 14, 2012: A gunman opened fire at a Sandy Hook Elementary School in Connecticut. At least 27 people died, including 20 children, according to reports. That story is still developing.
DON'T MISS: How James Holmes Went From Shy Nerd To Accused Cold-Blooded Killer >
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