(NewsNation) — Several of Sean “Diddy” Combs‘ accusers could soon be called to testify before a federal grand jury, according to reports, an indication of a potential indictment moving forward against the disgraced music mogul. 

Federal investigators have already notified multiple witnesses that they could be brought in to testify in front of a federal grand jury in New York City, CNN reported.

These witnesses are those who have brought civil suits against him, the outlet reported, adding that the potential witnesses have not yet been prepped for testimony.

While it’s still unclear if an indictment could be coming, investigators are taking ample time to build a case so it’s “bulletproof,” a source familiar with the investigation told the outlet.

Most of Combs’ accusers who have sued Combs have already been interviewed by federal investigators, some multiple times, CNN reported.

The music producer has been slapped with seven civil suits, each containing a multitude of disturbing accusations. He was also named in a civil suit filed against his son Christian Combs. 

Singer Casandra “Cassie” Ventura, who had been in a decadelong relationship with Combs in the early 2000s, filed a bombshell lawsuit in New York federal court last November alleging sex trafficking, human trafficking, sexual battery, sexual assault and gender-motivated violence, among other causes of action. 

Combs has denied all the allegations but did issue an apology after hotel surveillance video from 2016 obtained by CNN showed Combs violently attacking, kicking and shoving Ventura. 

Homes belonging to Combs were raided by federal investigators two months ago and the hip-hop mogul has not been charged, but that doesn’t mean a legal case isn’t coming, say former federal prosecutors. 

Department of Homeland Security agents conducted raids March 25 at Combs’ multimillion-dollar mansion in Los Angeles and his Miami waterfront home, sparking widespread speculation about what prompted the searches. 

Since then, little is still known about the investigation, likely because prosecutors are still building a case, Nadia Shihata, who prosecuted R. Kelly for sex crimes in New York, told NewsNation. 

Shihata said the complexity of this particular case will require a significant amount of time for fact-finding.

“I suspect they are potentially looking at building a racketeering case, and a lot of it is going to be based on testimony of witnesses and potential victims, and that takes a longer time to build because you have to speak to a lot of people and then you have to corroborate as much information as you can so you can prove your case beyond a reasonable doubt,” she said.

Investigators collected a lot of evidence after the raids, including electronic devices and phones, and they will need to go through all of that and analyze it carefully, she said. 

They are also likely interviewing a lot of people right now, including other potential victims, former and current employees or even members of his entourage, she added.

Federal authorities have given sparse public comment as to what prompted the raids, but NewsNation affiliate WPIX reported that it was part of an ongoing sex trafficking investigation. 

Authorities are reportedly widening their probe to include potential witness intimidation, sexual assault and firearms violations, according to a New York Post report. Reports have also indicated that the federal probe into Combs could expand to include reinvestigating a 1999 shooting outside a New York City nightclub.