Matviyenko, who is nominally the third most powerful politician in Russian Federation, said the case had been taken under the personal control of Yury Chaika, the prosecutor general.
Interior Minister Vladimir Kolokoltsev said the criminal case against Mr. Golunov was being dropped over a lack of evidence of any wrongdoing on his part. In a surprising turnaround, Russia's police chief on Tuesday dropped all charges against a prominent investigative reporter whose detention sparked public outrage and promised to go after the police officers who tried to frame the journalist as a drug-dealer.
The Russian investigative media outlet Project cited unnamed Kremlin officials on Monday as saying the presidential administration wanted police to drop charges against Golunov because they were anxious Putin would face awkward questions during the live call-in show.
Mr Golunov's reporting incorporated coverage of the loan shark industry, the earnings of the family of Moscow's deputy mayor, the strangely high sign of public works within the Russian capital, and the alleged censorship of journalists.
On Tuesday, the New York Times, which has blacked out nearly entirely the US-led persecution of Assange and Chelsea Manning and the protests internationally against their detention, reported extensively on the arrest of Golunov and protest actions against it under the headline "Reporter's Arrest Sets Off Widespread Protests in Russian Federation".
Earlier, the Secretary General of the Council of Europe, Thorbjørn Jagland expressed concern that the journalist had been subjected to violence by police officers and was injured while being placed in the police station.
"I will now have to work harder to justify your confidence in me", Golunov said pledging to continue his investigations as he left the Investigative Committee building.
Most Russian observers believe the Kremlin had no direct stake in Golunov's arrest, which most suspected had been brought about by mid-level officials or others involved in regional rackets that he most frequently wrote about.
Judicial statistics indicate that the chances for criminal charges to be dropped or an acquittal once a person is in custody are extremely slim.
Police on Saturday released several photos, reportedly from the journalist's home, of what appeared to be a drugs lab. "We demand the law be respected by everyone and for everyone".
He faced 20 years in prison if convicted on the drug manufacturing and supply charges for which he had been arrested.
Three major business-focused newspapers, Vedemosti, RBK and Kommersant ran front pages headlined "I/We are Ivan Golunov" in an echo of the "Je Suis Charlie" movement in France after the murder of journalists at the satirical newspaper Charlie Hebdo.
The circumstances of the journalist's arrest have alarmed the media community. In a separate statement later, the police said they found cocaine at his place. "This is just the beginning, a lot of work lies ahead".