Michael Cohen’s recent media interview has some commentators suggesting that Cohen will cooperate against President Donald Trump.

But at the moment, prosecutors seem to be saying “Don’t call us, we’ll call you.” What’s the delay? Here are some general rules of cooperation that Cohen should keep in mind.

The first rule is that prosecutors must gather relevant facts about a potential cooperator before talking with him so that they can probe the full extent of his knowledge.

Under exigent circumstances, of course, prosecutors would talk with a defendant immediately, but in a white collar investigation, it is more important to be fully informed before talking with a cooperator.

In Cohen’s case, prosecutors from the U.S. Attorney’s Office for the Southern District of New York, which is handling the matter, have not yet received all of the materials that were seized during the execution of a search warrant at his office, home, and hotel room. That’s because a judge appointed a special master, a retired federal judge, to review the materials for attorney-client privilege first. The documents are being handed over to prosecutors in batches. Only upon completing their review of the search materials would prosecutors be prepared to question Cohen.

Prosecutors will want to confront him with email messages, handwritten notes, financial documents, and recordings of telephone calls, among other things, to probe the full extent of his knowledge even beyond that which he is willing to volunteer. Only by having access to all of the search materials will prosecutors be able to fully utilize Cohen’s value as a cooperator.

The second rule is that prosecutors want to corroborate the statements of a cooperator because of the understandable skepticism with which jurors view cooperators. This, too, contributes to the delay that Cohen is facing.

Despite President Trump’s statement in a tweet that “most people will flip if the Government lets them out of trouble, even if it means lying or making up stories,” the government works hard to avoid this scenario by corroborating a cooperator’s statements with objective evidence. One of the best ways to corroborate a cooperator is with his own documents, such as phone records, credit card statements, and email messages that match his testimony. Some of those documents can be obtained from third-party service providers, but, in Cohen’s case, some of this evidence remains in the search material.

“ There is a natural temptation to be proactive and do things that will improve one’s destiny. Before taking action, though, defendants are well-served to listen to the advice of their attorneys. ”

Prosecutors will want to have that material reviewed and catalogued before talking to Cohen so that they can confirm whether he is telling them the truth, and so that they can use those items as exhibits at trial to convince a jury or other fact-finder that his testimony is accurate.

The third rule is that before making any charging decision or offering any plea deal, prosecutors want to understand the full extent of a defendant’s culpability. A typical plea offer requires a defendant to plead guilty to the most serious, readily provable offense. Prosecutors would not want to bargain away in a plea deal more serious crimes of which they are not aware.

A review of all of the materials obtained in the search is needed to satisfy prosecutors that Cohen has indeed committed a crime, and that they are not charging him with a lesser crime than the most serious one that he may have committed.

The fourth rule is that cooperators should keep their mouths shut before their case is complete. While Cohen complimented FBI agents in his interview, he also said he will “put family” first. Any statements a cooperator makes can be used against him on cross-examination to undermine his credibility.

A statement that he puts his family first can suggest that he is willing to cooperate to stay out of prison for the sake of his family, or that he is willing to lie to stay out of prison to provide for his family. Such statements harm his potential value as a cooperator.

The final rule is that the waiting is the hardest part. Criminal defendants have expressed that the most stressful times for them were not when they were serving their prison sentences but when they were waiting to find out their fates.

Waiting for the other shoe to drop in the form of criminal charges or sentencing can be the most difficult time for a defendant. There is a natural temptation to be proactive and do things that will improve one’s destiny. Before taking action, though, defendants are well-served to listen to the advice of their attorneys. Sometimes you just have to wait.