Authorities are now offering a $10,000 reward for information leading to the arrest of a second suspect in a shooting that injured four students at the Atlanta University Center.

The reward was previously $6,000 after two Atlanta City Council members offered contributions. The Atlanta University Center Consortium has contributed an additional $4,000, Atlanta police said Thursday.

Isaiah Williams, 21, turned himself in last week on charges he opened fire in a crowd of about 200 people in front of the AUC library. Investigators believe Williams and the second suspect were shooting at each other.

RELATED: Police release new video of second suspect in Atlanta University Center shooting

In surveillance footage released last week, the suspect can be seen fleeing the area in front of the library moments after the shooting. He appears to be wearing a black jacket with a white stripe on each sleeve, according to police.

The shooting occurred Aug. 20, just hours before the start of the new school year. A crowd had gathered outside the library for a block party when shots rang out about 10:30 p.m.

University officials have said the event was unsanctioned and planned by a third-party event company.

The victims, two Spelman College students and two Clark Atlanta University students, were taken to a hospital with injuries ranging from graze wounds to gunshot wounds, according to Atlanta police.

They were identified as 18-year-old Erin Ennis of Powder Springs, 18-year-old Maia Williams-McLaren of Boston, 18-year-old Elyse Spencer of Rochester, N.Y., and 19-year-old Kia Thomas of Jonesboro. None was seriously injured.

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“Initial investigation seems to indicate an argument broke out between two parties prior to the shooting,” Atlanta police public affairs director Carlos Campos said at the time. “It appears the women were not the intended targets of the shooting.”

Williams, the shooting suspect, is not enrolled at any of the AUC institutions. He was arrested last Wednesday on charges of aggravated assault, aggravated battery, possession of a firearm during the commission of a felony and criminal attempt to commit murder.

RELATED: 21-year-old charged in Atlanta University Center shooting

Williams waived his first appearance hearing last week, but his attorney, Bruce Harvey, told Channel 2 Action News his client should have been given a bond.

“This is a young man that’s never, ever been in trouble before,” he told the news station. “... We’re here to contest these charges.”

Police are asking anyone who recognizes the suspect to come forward, and they are still looking to speak with witnesses.

Tipsters can remain anonymous, and be eligible for rewards of up to $2,000, by contacting Crime Stoppers Atlanta at 404-577-8477, texting information to 274637 or visiting the Crime Stoppers website.