Law enforcement officers investigate the day after the April 15 shooting at a venue in downtown Dadeville, Alabama.
CNN  — 

State investigators found 89 shell casings and believe seven guns were used at a dance studio shooting that left four people dead during a Sweet 16 party in Dadeville, Alabama, earlier this month, according to a report from CNN affiliate WBMA.

The new details came Tuesday during testimony from an Alabama Law Enforcement Agency special agent at a bail hearing for several shooting suspects, according to WBMA.

The six suspects charged in connection with the massacre were denied bond, according to the district attorney’s office of the 5th Judicial Circuit of Alabama.

Five of the suspects were ordered to be held without bond until the trial and are being treated as adults, a news release from the office said. A sixth suspect, who is 15, was also denied bond at a separate hearing because he is a minor, according to a separate release.

Another new detail came to light as the investigator testified one of the deceased victims may have fired first, according to CNN affiliates WTVM and WFSA.

Corbin Holston, 23, was found dead inside the dance studio with a gun on his chest, the investigator reportedly told the court.

The party for 16-year-old Alexis Dowdell was in full swing when gunfire erupted, witnesses said. Alexis’ 18-year-old brother, Philstavious “Phil” Dowdell, was killed, along with Marsiah Emmanuel Collins, 19; Shaunkivia “Keke” Nicole Smith, 17; and Holston, the Tallapoosa County coroner said.

The state investigator testified that as many as 60 people were inside the dance studio at the time of the shooting, WTVM And WFSA reported.

Tyreese “Ty Reik” McCullough, 17, Travis McCullough, 16, Wilson LaMar Hill Jr., 20, Johnny Letron Brown, 20, Willie George Brown Jr., 19, and the unnamed 15-year-old have all been charged with four counts of reckless murder for their alleged involvement in the April 15 shooting that killed the four people and injured 32 others, including 15 who a hospital spokesperson said were hit by gunfire.

“The State intends to file a motion to transfer that juvenile to be tried as an adult,” the DA’s office said. “The Juvenile Court will have a hearing to determine whether or not he will be transferred and tried as an adult.”

CNN has attempted to reach a representative for the accused.

The hearing for the Browns and Hill was open to the public, while the McCulloughs’ session was closed, according to the three affiliates, which said the sixth suspect was not in court.

Authorities have not said what connection, if any, the suspects had to Alexis’ birthday party.

CNN has reached out to the Alabama Law Enforcement Agency for comment.

Authorities have not publicly discussed a motive in the killings that stunned the small Alabama city and joined it to a slew of other American communities grieving gun violence this year. The shooting is one of more than 173 mass shootings – in which four or more people were shot, excluding the shooter – reported in the US so far this year, according to the Gun Violence Archive.

CNN’s Isabel Rosales, Holly Yan and Elizabeth Wolfe contributed to this report.