Lang had been an officer for nine years, joining the elite Organized Crime Unit in 2011. That morning, when police rushed into a house to search it, a man grabbed a pistol with a high- capacity clip and fired. He wounded one officer and killed Lang.
"She was a hard charger," said Michael Williams, president of the Memphis Police Association. "She was compassionate. She was well-liked. She was one of the good ones."
The youngest of her daughters is 2.
At 11 a.m., 450 miles away, a police shoot-out ended differently after officers stopped a car at a Dallas apartment complex. Amid a struggle, the driver brandished a weapon and police shot him, according to a statement. Lenny Ellis, 30, died at the scene.
At 12:14 p.m., as the enormity of the Newtown massacre was becoming known, police in Cornwall, N.Y., a town of 12,600 by the Hudson River, were dispatched to Joseph Oliva's home on Mine Hill Road.
Oliva, 58, had sent a text to his sister in Virginia: "Goodbye. Take care of my daughter."
Then he killed himself with a Glock pistol. His wife, Sandra, 54, was in her bed, with a single shot to the head.
Police Chief Todd Hazard said there was no note or explanation. "He's probably the only one who knows," he said.
In Marshall, N.C., with a population of about 900, James Lagrua, 61, spent part of the day watching coverage of the Sandy Hook shooting at his home off the Appalachian Trail. He had a shotgun and two handguns.
Lagrua recently came out of retirement to work as a home health-care nurse, according to Michael Garrison, chief deputy of the Madison County Sheriff's Office.
At 9 p.m., his wife's daughter called 911 and barricaded herself in the basement of the three-story home with her two teenage daughters. Upstairs, police say, Lagrua shot his wife, Stephanie, 58, in the kitchen. He then shot his wife's 86-year- old bedridden mother, Hilma Barnett, in the head. He shot the family dog, too.