HOUSTON --A grand jury investigating the alleged beating of a teenager by several Houston police officers heard from a very important witness on Wednesday afternoon. Police Chief Charles McClelland appeared before the panel, and tried to be as discreet about it as possible. We caught Chief McClelland leaving the building using a private exit, and he was equally private about why he was at the Harris County Criminal Justice Center. "Judge Lykos is a friend of mine, so I come over here from time to time," Chief McClelland said. Neither the Houston Police Department nor the Harris County District Attorney's Office would say why the chief was here, however sources tell Eyewitness News the chief was summoned by a Harris County grand jury to testify about the accused beating of Chad Holley by Houston police officers. Police say Holley, 15 at the time, was a burglary suspect and was chased by police back on March 23. A surveillance camera at a nearby storage center caught the alleged beating on tape. Eight Houston police officers from HPD's Westside Command are accused of beating Holley. Photos of the teen's injuries, allegedly at the hands of police, were made public. Houston police officers Phil Bryan and G. Saucedo were accompanied by their union attorneys to testify before a grand jury earlier this month. A third cop, Officer Raad Hassan, was also seen walking in. "Grand jury proceedings by their very nature are secret. And they're done that way for a reason. We don't want to compromise the integrity of the investigation or reveal witnesses or even charge certain people before a grand jury has ruled that there is probable cause to go forward," said Donna Hawkins with the Harris County District Attorney's Office. Eyewitness News has also learned that indictments, in the case, may be handed down to one or more police officers as early as Thursday, if the grand jury feels it's time to move forward. This particular grand jury is impaneled until July 31. "The evidence, they have requested and additional evidence has been presented to them, and when the investigation is complete and they have all the evidence before them, then theoretically, they will make a decision on the case," Hawkins said. Holley, now 16, has been charged with burglary. The FBI, Harris County DA's Office, and HPD's internal affairs division are all looking into the case. The eight officers involved remain on paid administrative leave from HPD as the investigation continues. While the grand jury is expected to release its decision on Thursday, it's not clear how many officers could be indicted. We will continue to bring you details on the officers' grand jury investigation on Eyewitness News and abc13.com.