Nancy Palmieri for The New York Times

Ready for something truly terrifying?

John Zawahri, the 23-year-old Santa Monica spree killer, tried to buy a gun in 2011 but was denied by the Justice Department for unknown reasons. So Zawahri, who suffered from mental illness, circumvented that firewall by building his own AR-15 semi-automatic rifle using parts he bought from various sources around the country.

CBS News with Scott Pelley reported Friday that the sale of most gun parts online is not regulated, except for one critical component: the lower receiver, which holds the mechanical parts of the gun, such as the trigger. A background check is required to buy one, but Zawahri got around that by buying a partially-completed lower receiver and modifying it, something gun enthusiasts call 80-percent guns. The resulting gun, which fired .223-caliber ammunition, was untraceable.

Zawahri killed five and wounded four during his 13-minute shooting spree on June 7. Here is today’s report.

—Jennifer Mascia

Friday:

Dionni Branch, 3, was sitting on her grandmother’s Columbus, Ohio, porch Friday night when a stray bullet lodged just below her hairline. A 4-year-old boy was wounded when a bullet entered through a window in his north Wichita, Kan., home early Thursday. A 9-year-old girl was accidentally shot in the stomach by someone riding a BMX bicycle near her home in the Kingsbridge section of the Bronx, N.Y., Friday night. An 11-year-old boy was shot in the midsection and a 16-year-old boy was shot in the back during two shootings an hour apart late Friday and early Saturday that are believed to have stemmed from an argument over territory in south Monroe, La.

A 13-year-old girl was shot in the leg and wounded when a 13-year-old boy was handling a gun and it discharged in Chesterfield County, Va., Thursday. A woman was shot multiple times by her boyfriend and killed after an argument in Porter Ranch, Calif., Friday morning. Devonta Marquise Rayford, 17, a student at Stivers School for the Arts, was found dead of multiple gunshot wounds in a car in Trotwood, Ohio, Thursday. Benjamin D. Jackson, 24, was shot and killed at a Topeka, Kan., apartment Thursday afternoon. Two people were charged in the death of Antonio Booker, 27, who was shot and killed while attending an anti-violence vigil in Detroit, Mich., last weekend.

Laron McCoy was found shot dead inside an apartment in Midwest City, Okla., Thursday, and Santonio Johnson was shot and wounded. A man was shot in the chest and killed after an argument outside the Picante Sports Cantina in Fort Worth, Tex., early Friday. 20-year-old Dustin Daniel Pilkington was shot in the torso with a .25-caliber semi-automatic weapon near Bridwell Park in Wichita Falls, Tex., Thursday evening. A man was shot and critically injured near Central New Mexico Community College in Albuquerque, N.M., Thursday afternoon. A parolee shot two bystanders in the Lawndale neighborhood of Chicago, Ill., Thursday morning.

29-year-old Michael Payne was shot multiple times and killed in Buffalo, N.Y., Friday afternoon. A shooting in Blount County, Tenn., sent one person to the hospital Friday. 22-year-old Allen Parker III was shot three times and critically wounded at an intersection in Duquesne, Pa., late Friday afternoon. A 25-year-old man nicknamed “Big Mike” died on a Patterson, Calif., street Thursday night after someone shot him in the head in an episode of gang-related violence. 28-year-old Daniel Jolly was shot in the arm and wounded during a fight over a poker game in El Mirage, Ariz., Friday morning. A man was shot and killed by his 20-year-old friend in Glendale, Ariz., late Wednesday night.

Nicole Luke, 34, her 15-year-old daughter and her 14-year-old twin daughters were shot and critically wounded by Luke’s boyfriend at an apartment complex in Nashville, Tenn., Friday afternoon. One person is fighting to survive after being shot Friday afternoon in Kansas City, Mo. Four people were injured in a shooting in High Point, N.C., Friday night. A man sustained a gunshot wound to the arm in Milwaukee, Wis., Thursday night. Someone was shot in the stomach on Milwaukee’s north side Friday morning. A woman was shot and killed on the front lawn of a home by her boyfriend, who then engaged in a five-hour standoff with police in Northridge, Calif., early Friday.

A 20-year-old man suffered multiple gunshot wounds when someone got out of a luxury sedan and began shooting at him in a north Stockton, Calif., neighborhood Thursday afternoon. A shooting left a 24-year-old man critically wounded in North Philadelphia, Pa., Friday morning. A 31-year-old man was found lying dead with a gunshot wound to the head in a North Philadelphia street Friday night. Tony Youngblood, 30, was shot during an armed robbery at an apartment in Okaloosa County, Fla., Thursday night. One person was shot after an argument escalated at a nightclub in Lake City, S.C., late Friday.

Carmen Denise Dean, 42, was shot while parked in her driveway and drove herself to the hospital in Valrico, Fla., early Friday. A 26-year-old man suffered a gunshot wound to his leg as he rode in the bed of a truck in Nikiski, Alaska, early Friday. Three people were injured in a shooting while stopped at an intersection in the Bayview District of San Francisco, Calif., Thursday evening. A 22-year-old man is in critical condition after being shot in the chest near the Charles Village area of Baltimore, Md., early Friday. A 37-year-old man was shot multiple times as he ran along a Springfield, Mass., street looking for a place to hide early Friday.

Michale Shook, 63, was shot and killed by his daughter’s ex-husband in Fort Smith, Ark., Thursday. A woman was shot with a rifle by her husband at their home in Brooke County, W. Va., Friday evening, before he turned the gun on himself. Emily Hazelbaker, 18, was accidentally shot and killed by her father, Scott Merle Hazelbaker, at the Delaware Crossing Apartments in Ankeny, Iowa, Friday evening. Police are investigating a murder-suicide in northwest Las Vegas, Nev., Thursday. At least eight people were wounded, including three teenagers, in shootings across Chicago, Ill., overnight.

Joshua Floyd Council, 22, was shot and killed Friday night when someone in a vehicle opened fire into a crowd on a basketball court in Lumberton, N.C. Randal Ray Gallagher, 43, was found dead of what was initially reported as a self-inflicted gunshot wound but what police are now investigating as a homicide in Klamath County, Ore., Friday night. A man was wounded in a shooting at the Ashley Oaks Apartments in Charleston, S.C., Friday night. 49-year-old Scott Daniel McBride was shot and killed after an altercation in Carlisle County, Ky., Friday night. A man was shot in the stomach and wounded in a gang-related attack in the South Bay area of San Diego, Calif., Friday night. A man was shot in the face and stomach in Cathedral City, Calif., Thursday night.

Saturday:

A 30-minute shooting spree left two people dead and two critically injured south Omaha, Neb., Saturday afternoon. A man was shot and killed and two others were sent to the hospital, including a small child, after an argument between two people at a gas pump at an ARCO station in Sacramento, Calif., Saturday. A man was shot in the hand following a fight at a gas station on the northwest side of Grand Rapids, Mich., early Saturday. Edward Duckett, 18, was shot in the back, leg and hand during a gunfight in Chattanooga, Tenn., early Saturday. Spencer McPherson, 20, was shot in the back while he was sitting in his SUV in Chattanooga Saturday evening.

A 10-year-old was shot and wounded by a 15-year-old during a Juneteenth festival in Columbus, Ohio, Saturday night. Joshua Lapsley was shot in the arm in Huntington, W. Va., after two men opened fire and took off running just after midnight Saturday. A 19-year-old man was shot in the back and wounded in Wilmington, Del., early Saturday. A shooting at a restaurant and bar in the Bearden area of Knoxville, Tenn., sent two men to the hospital early Saturday. Shane Christopher Newman, 38, died and a 22-year-old man was injured after a shooting at a house in northwest Lincoln, Neb., early Saturday.

A woman was shot and wounded at the Mansion Night Club in McRae, Ga., after arguing with another woman. 17-year-old Shaquez Jackson and 18-year-old Davarea Sandifer were wounded when an unknown person opened fire at a Ramada Inn in Warner Robins, Ga., early Saturday. A 28-year-old man was shot in the upper back after an argument among a gathering of men in Inwood, Long Island, N.Y., early Saturday. A man was shot in the head and killed in northwest Baltimore, Md., Saturday evening. Two people were shot and wounded in the courtyard behind La Rumba, a bar in Knoxville, Tenn., early Saturday.

Esequiel Gloria drove himself to a gas station to get help after being wounded in a drive-by shooting in San Antonio, Tex., early Saturday. Steven Lacey White, 62, was shot in the chest and killed by his son, 40-year-old James Jason White, in Tyler, Tex., late Saturday. A 35-year-old man was shot at the entrance of at a south Springfield, Mo., convenience store early Saturday. A 24-year-old man was shot in the foot after an argument in Springfield, Mass., early Saturday. A man was shot in the foot during an altercation with a neighbor in Savannah, Ga., Saturday night.

Two men were hospitalized after an altercation led to a shooting at a west Chatham County, Ga., apartment complex Saturday afternoon. A 17-year-old boy was shot once in the back in Erie, Pa., late Saturday. A 22-year-old man was shot while standing on a porch in Syracuse, N.Y., early Saturday. Three people were shot and wounded at a home in Wilkinsburg, Pa., late Saturday. Inis Amigon, 44, was shot and killed and a 24-year-old woman and a 29-year-old man were wounded near El Molino Restaurant in Poughkeepsie, N.Y., overnight. Wayne Hebert, 45, was shot multiple times in the back and killed by his older brother, 51-year-old Michael Hebert, after an argument at the victim’s Baton Rouge, La., home early Saturday.

A woman shot and killed during a robbery at a flower store in Webster, Tex., Saturday evening. A man in his early 20s was shot several times and wounded in Mead Valley, Calif., early Saturday. 29-year-old Michael Moore was found shot to death in a car in Albuquerque, N.M., early Saturday. A man is in serious condition after being shot multiple times on the southeast side of Fort Wayne, Ind., early Saturday. A 22-year-old man was standing outside a house in Wichita, Kan., early Saturday when someone shot him in the elbow. Two men, both 23, were shot multiple times after a physical altercation near the beachfront promenade in Ventura, Calif., early Saturday.

A 14-year-old boy was shot in the chest and a 23-year-old woman was shot in the arm near the Mahoney Playground in the New Brighton section of Staten Island, N.Y., Saturday night. A shooting near a highway exit ramp in Forest Park, Ohio, sent two people to the hospital Saturday evening. Richard Evans, a father of three, was shot and killed during an attempted robbery at his eatery, Cosmic Pizza, in the Hartwell neighborhood of Cincinnati, Ohio, Saturday evening. A man in his 20s was found behind a building in Roxbury, Mass., suffering from a life-threatening gunshot wound early Saturday.

A man in his 30s was pronounced dead at the scene of a shooting in Mattapan, Mass., Saturday afternoon. A man and woman were shot and dropped off on a front lawn more than two miles away in Miramar, Fla., early Saturday. A 40-year-old woman is in stable condition after being shot in the leg in Hartford, Conn., early Saturday. A 28-year-old man was injured following a targeted drive-by shooting in Pawtucket, R.I., Saturday afternoon. Three men were shot and wounded outside a downtown Anchorage, Alaska, nightclub after a verbal argument escalated early Saturday. A man was killed and three other people were wounded after a man fired nearly a dozen shots outside an after-hours club in southwest Houston, Tex., early Saturday.

A 23-year-old man was killed and two teenagers were injured after a shooting in Camden, N.J., Saturday evening. A shooting at an apartment in central Henrico County, Va., left a man dead Saturday evening. A man in his early 20s was shot and killed at the Gilpin Court housing project in Richmond, Va., early Saturday. Tiara Green, 19, was killed and two others were wounded in a drive-by shooting behind the Rowan Towers apartment complex in Trenton, N.J., late Saturday. A woman and a man were shot and wounded in Visalia, Calif., Saturday evening. A 18-year-old man was shot to death while attending a child’s party in Vallejo, Calif., late Saturday.

A man was shot twice while exiting a car outside a home in Jacksonville, Fla., late Saturday. A man in his early 30s was found shot to death on a San Bernardino, Calif., sidewalk early Saturday. A 75-year-old woman was shot and killed by her 76-year-old husband in their Cortlandt, N.Y., home following an argument early Saturday. A 21-year-old man was shot in the hand and wounded in the Lincoln Park neighborhood of Duluth, Minn., late Saturday. A man in his 40s was found shot to death in his truck at the Ashmark Arms apartment complex in Fresno, Calif., Saturday night.

A 16-year-old boy and a 24-year-old man were shot and wounded while walking on Portland Avenue in Rochester, N.Y., late Saturday. A man was shot twice in the arm with a semi-automatic weapon in what police believe is a gang-related attack in Seaside, Calif., Saturday night.

Sunday:

A 35-year-old man walked into a Catholic church in Ogden, Utah, and shot his father-in-law in the back of the head during Sunday morning mass. A man accidentally shot and wounded his grandson in Lawrence County, Ala., Sunday morning. An 11-year-old boy was grazed by a bullet from a passing car while he was sleeping in his bed in Oakland, Calif., Sunday morning. Someone opened fire on a group of people outside a Providence, R.I., house just after midnight, killing a 12-year-old girl. The body of Mark V. Fisher, 48, was found at a Casper, Wyo., shooting range early Sunday with a single gunshot wound to the chest.

A man shot in both shoulders flagged down an ambulance on Interstate 4 in Orlando, Fla., Sunday afternoon. Frederick D. Watson, Jr., 20, was found shot to death between the passenger and driver seat of a vehicle at an intersection in West Toledo, Ohio, early Sunday. Two men, both 22, were killed and a 23-year-old man was seriously wounded in a shooting at a street corner in northwest Fort Worth, Tex., early Sunday. A 48-year-old woman was shot three times and critically wounded in the Kensington neighborhood of Philadelphia, Pa., Sunday afternoon. A 27-year-old man was shot twice in the chest and killed on a Philadelphia basketball court Sunday afternoon.

A 23-year-old woman was shot in the leg during a fight inside the Potawatomi Bingo Casino in Milwaukee, Wis., early Sunday. A man is in serious condition after being shot in a drive-by shooting in south St. Louis, Mo., early Sunday. A man was shot in the torso inside a home in Longview, Tex., Sunday afternoon. A man in his early 20s was shot in the stomach during a fight at an Elk’s Lodge in Muskegon, Mich., early Sunday. Two people were injured during a shooting at the Best Food Mart in Lexington, N.C., Sunday afternoon. 47-year-old George Reavis was critically wounded after being shot multiple times by his wife, 42-year-old Diana Matthews, at their Zephyrhills, Fla., home Sunday morning.

A man was shot in the thigh and another man was shot in the shoulder in two separate shootings overnight in Hartford, Conn. A 21-year-old man was wounded in a possibly gang-related shooting in Valencia Park, Calif., Saturday night. Keith Anthony, 24, was fatally shot outside a house party in the Flatlands area of Brooklyn, N.Y., early Sunday. A man was found lying on a sidewalk after a shooting in Colorado Springs, Colo., Saturday night. 18-year-old Brendon Ford and 17-year-old DMarco Pope were killed in a gang-related shooting in north Omaha, Neb., early Sunday. 22-year-old Tony Muse was found dead at the scene of a shooting near Lafayette Square Mall in Indianapolis, Ind., early Sunday.

24-year-old Krista Avery was hospitalized after a drive-by shooting in Henderson, Nev., Sunday evening. Officers were called to a pair of shootings in Pittsfield, Mass., that sent four people to the hospital early Sunday, but police are not sure if they’re related. 23-year old Quenton Alexander was found dead of gunshot wounds in a car near a Motel 6 in Conway, Ark., early Sunday. One person was shot and critically wounded in the Lanark area of Raleigh County, W. Va., early Sunday. An unidentified person was shot in the face and hospitalized in Mount Hope, Ala., early Sunday. At least seven people died – including a 16-year-old – and 41 others were wounded in shootings across Chicago, Ill., this weekend. It was the most violent weekend so far this year in that city.

According to Slate’s gun-death tracker, an estimated 5,090 people have died as a result of gun violence in America since the Newtown massacre on December 14, 2012.