Worth noting that indictments are laughably easy to get, because there is no defense lawyer. An indictment isn’t a conviction, it’s just the prosecution going “yeah we probably have enough evidence to bother with a trial.” The old joke is that a grand jury will indict a ham sandwich for murder if the prosecutor wants them to. The prosecutor has full control over what evidence the grand jury sees, and the rules around evidence are a LOT more relaxed than they are in court. The prosecutor could basically scribble out a “yeah I did it lol” note on a napkin and present it to the grand jury as evidence. It wouldn’t stand up in court, but it doesn’t need to if the prosecutor just wants the indictment.
The grand jury is just an arm of the prosecutor, and is used as a political tool whenever a trial would be politically inconvenient. Because the district attorney is typically elected, which means they need to pander for votes. So if it would be politically inconvenient to prosecute someone, they can simply refuse to bring any evidence to the grand jury. Because (again) they have full control over what evidence the grand jury sees.
For example, let’s say a cop murders someone in the street. It’s on video. The public is out for blood. But the prosecutor has to work with the police to do their job, and the police union is threatening to stop collecting any evidence at crime scenes if they prosecute this cop. Prosecutor is between a rock and a hard place, because they’d be torching future trials just to appease the public. So instead, they simply don’t bring any evidence to the grand jury. The grand jury is a faceless shadowy organization that can’t defend itself. It’s the perfect scapegoat. So when the grand jury refuses to indict (because they weren’t presented with any evidence) the district attorney can jump in front of the news cameras and go “I tried to prosecute them, but that big mean grand jury refused to indict. But remember, I did my best! Vote for me!” Cops are happy because the prosecutor didn’t indict, the public is placated because the prosecutor “tried” to indict them, and the cogs of the legal system keep grinding away as intended.
So with all of that being said… If he wasn’t indicted, it’s because the prosecutor didn’t want to bring it to trial.