Five former Moscow police officers have been detained in the high-profile drug-trafficking case against Russian investigative journalist Ivan Golunov, who was arrested and then released amid a public outcry and allegations of police corruption in June 2019.

The Investigative Committee said on January 29 that the detained officers from the Moscow antidrug unit are currently being questioned.

In its second statement the same day, the Investigative Committee said former officers Denis Konovalov, Akbar Sergaliyev, Roman Feofanov, Maksim Umetbayev, and their former supervisor, Igor Lyakhovets, were suspected of planting drugs in Golunov's backpack and apartment.

"The investigation has established that the officers intended to illegally file criminal charges against Golunov and...falsified the results of evidence-gathering operations which then served as proof of Golunov's guilt," the statement says.

It says that "the drugs planted [in Golunov's apartment and backpack] had been illegally obtained and also illegally carried by the police officers."

The Investigative Committee's statement is a very rare admission of wrongdoing by Russian law enforcement agencies.

The 37-year-old Golunov, who works for Latvia-based Meduza, was arrested in June in Moscow for allegedly attempting to sell illegal drugs.

He was released several days later after the charges were dropped following a public outcry. The case sparked an investigation into his detainment over the charges and also into why Golunov suffered bruises, cuts, a concussion, and a broken rib during the ordeal.

In mid-July, three police officers and their supervisor were fired for violating Golunov's rights while detaining him.

After Golunov's release, Russian President Vladimir Putin fired Major General Yury Devyatkin, the head of the Moscow police department's drug-control directorate, and Major General Andrei Puchkov, the police chief in Moscow's western administrative district, over the case.

Authorities announced in November that the case had been classified, a decision harshly criticized by Golunov's lawyers, who called the move an attempt to cover up the "wrongful arrest" of their client.