Diddy Prosecutors Might Interview New Witnesses in Ongoing Sex Trafficking Probe

The investigation into Diddy is far from over ... with sources telling TMZ at least one person has been subpoenaed to testify in front of the grand jury -- and we're told others are open to cooperating with federal prosecutors.

Sources with direct knowledge tell TMZ ... at least two new people plan to cooperate with the feds' ongoing investigation of Diddy and are willing to testify in front of the grand jury in the coming days.

We're told one of these people is a current sex worker ... who claims they were involved with Diddy back in 2014.

Beyond the grand jury investigation, we're told the feds are still gathering info and interviewing witnesses ... and, our sources say they've reached out to at least one sex worker that we know of.

We've been in contact with this sex worker ... who says they plan to be interviewed by feds in NYC later this month.

The federal case against Diddy has ramped up in recent days ... with feds arresting the rap mogul in NYC Monday night. The grand jury's already indicted him on racketeering conspiracy, sex trafficking by force, fraud or coercion and transportation to engage in prostitution.

Diddy was denied bail twice -- just yesterday, a judge reaffirmed the previous decision to hold him without bail pending trial, and he currently remains behind bars at New York's notorious detention center, MDC Brooklyn.

Diddy's lawyer, Marc Agnifilo, says he's working to get his client out of that facility, and into better accommodations ... all while Diddy remains focused on his defense.