Moscow's Basmanny district court has arrested five people in connection with the murder of Boris Nemtsov, a prominent opposition figure, who was gunned down last week.

Two judges are reviewing the charges against the five people brought before the court by the prosecutors on Sunday.

Two of them are Zaur Dadaev and Anzor Gubashev, who were identified as key suspects in the killing of Nemtsov after their detention on Saturday.

The prosecutors asked the court to arrest the duo by April 28, the current deadline for the investigation, saying that otherwise they may flee or interfere with the investigation.

According to the judge, who ordered Dadaev’s arrest as requested by the prosecution, he confessed his involvement to the police. The accused didn’t comment on this during the court session.

Gubashev pleaded not guilty to the crimes he is charged with.

The other individuals, who may have had a hand in the crime, are Gubashev’s brother Shagit and two identified as Ramzat Bakhaev and Tamerlan Eskerkhanov. The request for their arrest has been reviewed separately by another judge.

“The suspects denied their ties to the crime, but we have evidence of their guilt. It includes forensic evidence and eyewitness accounts,”an investigator told the court.

The trio denied their involvement, with Eskerkhanov claiming to have an alibi. But the judge ordered their arrests as well.

Eskerkhanov and Bakhaev have been remanded until May 8 and Shagit Gubashev - until May 7.

The sixth suspect, Beslan Shavanov, 30, reportedly committed suicide on March 7, when police came to his apartment in Chechnya’s capital Grozny. The man, according to LifeNews channel, had barricaded himself in the apartment.

“In response to the police’s demand he surrender, he [the suspect] threw a hand grenade [at police forces],” a law enforcement source told the news channel. Shavanov then detonated another grenade, killing himself.

The President of the Chechen Republic, Ramzan Kadyrov, commented on the arrest of the five suspects on his Instagram account on May 8. He specifically spoke about Dadaev, saying he knew him “as a patriot of Russia” who used to serve as deputy regiment commander in one of the Chechen Republic’s interior ministry units.

Kadyrov has ordered a “thorough investigation” of Dadaev’s retirement from the unit, saying that he “does not understand true reasons and motives” behind his decision.

However, the Chechen leader noted that the suspect, as a deep believer, had been “shocked” by the Charlie Hebdo scandal and all the “comments in support of printing the cartoons.”

Kadyrov has also confirmed Shavanov “died during attempts to detain him”.

Nemtsov was killed by a gunman a few meters from the Moscow Kremlin, triggering a flurry of condemnations and calls for a swift investigation. The assassination happened two days ahead of an opposition rally, which Nemtsov helped to organize.

READ MORE: Opposition politician Nemtsov’s murder caught on CCTV camera (VIDEO)

While political motive is considered the most likely in the killing, the investigators said they were considering other scenarios, including a business or personal conflict. Likely political motives behind the killing according to the investigators include a provocation aimed at destabilizing the situation in Russia, possibly by Ukrainian radicals, and revenge by Islamists for Nemtsov’s support of the French magazine Charlie Hebdo following an extremist attack.