(Clockwise from top left) Tabari Young, 22; Bryon Champ, 21; Kewane Gatewood, 20; and Brad Jett, 22, each have been charged in connection with a shooting that wounded 13 people at a South Side park. Young allegedly fired an assault rifle, Champ also allegedly fired shots, Gatewood allegedly supplied the assault rifle, and Jett allegedly acted as a lookout. (Credit: Chicago Police)

Updated 09/24/13 – 10:04 p.m.

CHICAGO (CBS) — Two more people, including the alleged gunman, have been charged in a mass shooting that left 13 people wounded in the Back of the Yards neighborhood last week.

The latest charges come just hours after two other men were charged in connection with the shooting late Thursday at Cornell Square Park, at 51st and Wood streets.

“As of right now, we have four offenders charged in this shooting, including the man who fired that military-grade weapon, and a man who supplied that military-grade weapon,” Police Supt. Garry McCarthy said at a news conference Tuesday morning.

Tabari Young Tabari Young, 22, allegedly fired an assault rifle in an attack at Cornell Square Park, leaving 13 people wounded on Sept. 19, 2013. (Credit: Chicago Police)

Bryon Champ Bryon Champ, 21, allegedly fired a gun during shooting that wounded 13 people in the Back of the Yards neighborhood on Sept. 19, 2013. A second gunman fired an assault rifle in the attack. (Credit: Chicago Police)

Kewane Gatewood Kewane Gatewood, 20, allegedly supplied the assault rifle that was used in a shooting that wounded 13 people in the Back of the Yards neighborhood on Sept. 19, 2013. (Credit: Chicago Police)

Brad Jett Brad Jett, 22, allegedly acted as a lookout during a shooting that wounded 13 people in the Back of the Yards neighborhood on Sept. 19, 2013. (Credit: Chicago Police)

Deonta Howard Jr. Deonta Howard Jr. continues to recover at Mt. Sinai Hospital, after he was shot in the face at Cornell Square Park. Twelve other people also were shot on the basketball court at the park. (Photo supplied to CBS)

Deonta Howard Jr. Deonta Howard Jr. continues to recover at Mt. Sinai Hospital, after he was shot in the face at Cornell Square Park. Twelve other people also were shot on the basketball court at the park. (Photo supplied to CBS)

Deonta Howard Jr. and mother Deonta Howard Jr. and his mother, Shamarah Leggett, at Mt. Sinai Hospital. (Photo supplied to CBS)

Deonta Howard Jr. Deonta Howard Jr. continues to recover at Mt. Sinai Hospital, after he was shot in the face at Cornell Square Park. Twelve other people also were shot on the basketball court at the park. (Photo supplied to CBS)

Deonta Howard Jr. Deonta Howard Jr. continues to recover at Mt. Sinai Hospital, after he was shot in the face at Cornell Square Park. Twelve other people also were shot on the basketball court at the park. (Photo supplied to CBS)

13 Shot In Back Of The Yards Chicago police investigate after gunmen opened fire on a basketball court at a park in the Back of the Yards neighborhood, wounding 13 people, including a 3-year-old boy. (Credit: Scott Olson/Getty Images)

He said the man who fired an assault rifle in the attack — 22-year-old Tabari Young — has a record including more than a dozen arrests. Prosecutors said the weapon he fired was an AK-47.

Young and three other men — Brad Jett, 22; Kewane Gatewood, 20; and Bryon Champ, 21 — all have been charged with three counts each of attempted murder and aggravated battery.

The four were denied bail at a bond hearing Tuesday afternoon.

McCarthy said Gatewood supplied the assault rifle Young fired at the park. Champ also allegedly fired a gun during the attack, and Jett acted as a lookout, according to McCarthy. Prosecutors said Champ’s gun was a .22-caliber revolver.

“Today, we bring four criminals to justice for their roles in the shooting of 13 people, including a 3-year-old child,” McCarthy said.