Special counsel Robert Mueller's investigation could take years. With Michael Flynn pleading guilty Friday to lying to the FBI, CBS News justice reporter Paula Reid says, "If you have something to hide, Mueller's ability to keep his cards close the vest should make you nervous."

Flynn entered the guilty plea in federal court on Friday, and admitting to lying to the FBI as it investigated Russian interference in the 2016 presidential election. Flynn turned himself into the FBI early Friday morning and was processed and charged. Flynn's misleading of the FBI took place while Donald Trump was president-elect.

Read: Flynn statement of offense

Read: Flynn plea agreement

Reid noted that there were clues that Flynn would strike a deal, but the "explosive details" of what he told the special counsel were only revealed after his plea hearing.

"Special counsel Robert Mueller is a man of secrets and surprises," Reid said. "Just a month ago, we were all surprised by the plea deal of [George] Papadopoulos. He was a little-known campaign aide there had not been any hints that he was actively cooperating in the case."

As part of the investigation, the special counsel's office is looking at whether President Trump or anyone else attempted to obstruct justice by trying to tamp down the investigation into Flynn, Reid said. Testimony from Papadopoulos and Flynn helps investigators build cases around a new round of targets, Reid notes.

According to court documents released Friday, a "very senior member" of the Trump transition team in December 2016 directed Flynn to contact Russia and officials from other foreign governments to determine where they stood on a U.N. resolution about Israeli settlements, influence those governments and delay the vote or defeat the resolution. Three sources with knowledge of the situation said Friday that the "very senior member" of the Trump transition team was adviser Jared Kushner.