“You cannot consider an ordered killing a closed case as long as the organizers walk free,” Prokhorov added. “Here we did not have not one organizer on the defendant’s bench. This investigation is a fiasco.”

Judge Yury Zhitnikov sentenced Anzor Gubashev to 19 years in a high-security prison and his brother Shadid Gubashev to 16 years. Temirlan Eskerkhanov was handed 14 years and Khamzat Bakhayev 11 years, the Interfax news agency reports. The court also stripped Dadayev and Eskerkhanov of their military ranks and awards.

The defense has said they will appeal some of the court’s rulings.

“Everyone understands perfectly that Bakhayev and Eskerkhanov are innocent,” Eskerkhanov’s lawyer Anna Byurchiyeva told The Moscow Times. “But law enforcement does not want to admit it.”

“We expected a pardon,” Byurchiyeva added.

Prokhorov also said there was not enough evidence to convict Bakhayev, saying the punishment should be directed at organizers of the crime.

The five men, who are all ethnic Chechens, were charged with Nemtsov’s death in December 2015. A sixth suspect, Beslan Shavanov, killed himself with a grenade while resisting arrest.

The Gubashev brothers and Eskerkhanov traced Nemtsov’s movements prior to the killing, the court found. Bakhayev provided information and helped the group hide after the murder, the court was told during hearings.

The men were allegedly offered 15 million rubles ($240,000) to murder the politician.

Nemtsov’s legal team has said the men on the defendant’s bench were pawns in the politician’s killing. They claim the masterminds — naming former deputy commander in the Chechen special forces and Dadayev’s direct boss Ruslan Gereemeev — are being protected by authorities in a trail that leads directly to the North Caucasus republic of Chechnya and its leader Ramzan Kadyrov.

The investigation initially appeared to be progressing quickly, but stalled in May 2015 when the chief investigator working on the case was expectedly replaced.

“This is a very mild punishment,” opposition politician Ilya Yashin, a close friend of Nemtsov, told The Moscow Times after the sentences were announced. “The case on the organizers has its separate proceeding, but in reality no investigations are being done.”

“Our task is to make sure that the investigative actions continue and that all people who were involved in the organization of this murder are behind bars.”

Prokhorov is convinced that the organizers will ultimately be caught and put on trial.

“This chain is not particularly long or complex, but clearly the investigators have something blocking their way,” Prokhorov said. “The country’s powers are not allowing this case to be investigated in the proper way.”

“But I am absolutely convinced that this crime will be closed with time,” he added. “A crime of this magnitude, so well organized, cannot simply sink into the swamp.”