Michael Flynn has been in serious legal jeopardy since March, when it emerged that Donald Trump’s choice for national security adviser had failed to disclose payments from a Russian business. And for weeks now there’s been an accelerating drumbeat of stories insisting that special counsel Robert Mueller has plenty of evidence to indict Flynn. So what’s the hold up?

The delay doesn’t mean Flynn has been cleared. Instead, it appears the former general is entangled in so many strands of the Russia investigation that Mueller needs more time to run down all the leads. For instance: For years the Turkish government has pressured American politicians to return Reza Zarrab, a gold trader accused of violating U.S. sanctions against Iran. Mueller wants to know if Ankara enlisted Flynn, who in 2016 was a paid agent of Turkey as well as a Trump campaign adviser, in the effort to extradite Zarrab.

Last week, just as Zarrab was about to stand trial, he was suddenly and mysteriously transferred within the U.S. prison system, his new whereabouts undisclosed. Perhaps Zarrab was moved for his physical safety. Another strong possibility, former prosecutors say, is that Zarrab has become a cooperating witness. More dramatic are suggestions that Flynn discussed helping Turkish President Recep Tayyip Erdoğan with another problem: shipping an exiled political enemy, Fethullah Gülen, home from Pennsylvania, against his will. “There appear to be potentially indictable cases with respect to Flynn’s security forms,” says Kendall Coffey, who was a Florida U.S. attorney during the Clinton administration. “But if Flynn was negotiating with the Turkish government to assist in the removal of a political opponent, that couldn’t be ignored by Mueller, and it’s the kind of thing that can’t be thoroughly examined quickly.”

Flynn’s lawyers did not respond to a call for comment, though they did issue a statement responding to a Wall Street Journal story about Mueller’s interest in the Turkish angle. “Out of respect for the process of the various investigations regarding the 2016 campaign, we have intentionally avoided responding to every rumor or allegation raised in the media. But today’s news cycle has brought allegations about General Flynn, ranging from kidnapping to bribery, that are so outrageous and prejudicial that we are making an exception to our usual rule: they are false.”

Then there’s the dead body in a Minnesota hotel room. Peter W. Smith, a Republican political operative, committed suicide in May, about a week after reporters questioned Smith about his efforts to obtain Hillary Clinton’s e-mails from Russian hackers. Investigators have been trying to determine whether Flynn and his son were involved in pursuing those Clinton e-mails. “That suicide opened up a whole ‘nother chapter in the investigation,” says Democratic Congressman Mike Quigley, a member of the House Intelligence Committee. “We are still closer to the beginning of the investigation than the end.” (“No Foul Play Whatsoever,” read a suicide note left behind at the scene.)

The spate of imminent Flynn indictment stories may have been driven, according to Renato Mariotti, a former Illinois federal prosecutor, by Mueller’s push for third-party witnesses. “Prosecutors tell people they have enough evidence to indict when they want somebody else to cooperate against the target,” Mariotti says. “It might be lobbying firms or whoever else worked with Flynn. What the recent stories tell me is that Mueller is trying to get his evidence together and figure out who is going to testify against Flynn.”

Another possible reason for the hold up: Any discussions of a plea deal with Flynn would be complicated by the multiplying threads of the investigation. Mueller would not want to make an offer until he’s sure of all the possible charges he could lodge, to maximize his leverage and force the former general to testify truthfully about everything he knows. Especially his dealings with Donald Trump. “How much did Trump know about Flynn’s conduct?” Coffey says. “What were their conversations? Did Trump tell Flynn that he was getting a lot of help from the Russian government? Obstruction of justice requires a corrupt motive, a corrupt intent. I’ve thought for a long time that Flynn would be the key to whether you could ever have a compelling obstruction case here.”

Former F.B.I. director James Comey said that Trump, in a one-on-one February White House conversation, asked him to let the investigation of Flynn slide. When Comey didn’t, Trump fired Comey. “Mueller’s investigation of Flynn would certainly be relevant to obstruction, because you might uncover more things Trump knew about that Flynn had done,” Mariotti says. “But what matters for obstruction is what Trump knew—or thought he knew—about Flynn’s liability, not what Flynn’s liability actually was. Even if Flynn would have gotten off scot-free but Trump was convinced that Flynn was in deep trouble, and acted because of that belief, then Trump has a problem.”