In a significant development following the horrific attack on a suburban Moscow concert hall, nine individuals have been detained by Tajikistan's state security service on suspicion of having contact with the perpetrators, as reported by Russian state news agency RIA Novosti on Friday.

According to an unnamed source in Tajikistan's special services, the detainees, who are residents of the Vakhdat district, are believed to have had connections with the gunmen who carried out the terrorist attack at Crocus City Hall on March 22. The operation to apprehend the suspects involved collaboration between Tajikistani and Russian security forces.

The detained individuals are also suspected of having affiliations with the Islamic State (IS) group, RIA Novosti revealed. As investigations continue, a Moscow court ruled on Friday that Lutfulloi Nazrimad, another suspect in the concert hall attack, should remain in custody until at least May 22.

Nazrimad, who stated in court that he was born in Tajikistan, becomes the ninth suspect to face court proceedings in connection with the heinous attack. Russian officials had previously announced that 11 individuals were arrested, including four who allegedly carried out the assault. These four Tajik nationals appeared in a Moscow court on Sunday, showing signs of severe beatings and one appearing barely conscious during the hearing.

Adding to the investigation, the Russian Investigative Committee disclosed on Thursday that another suspect had been apprehended for suspected involvement in financing the attack on Crocus City Hall. However, no further details regarding the suspect's identity or actions were provided by the authorities.

The responsibility for the massacre has been claimed by a faction linked to IS, but Russian officials, including President Vladimir Putin, have consistently accused Ukraine and the West of being involved in the attack without presenting any evidence. The Investigative Committee's statement alleges that the terrorists received substantial amounts of money and cryptocurrency from Ukraine, which were allegedly used in planning the crime.

Ukraine has firmly denied any involvement, describing the allegation as a pretext for Russia to escalate its conflict in the country. Tensions between Russia and Ukraine have been ongoing for years, with Moscow annexing Crimea in 2014 and backing separatist movements in eastern Ukraine.

As the investigation continues, the death toll from the concert hall attack tragically rose to 144 on Friday. This increase came as a severely injured victim succumbed to their injuries in a hospital, according to Russian Health Minister Mikhail Murashko.

The international community continues to condemn acts of terrorism and urges countries to collaborate in the fight against extremism to prevent future tragedies. The ongoing investigation into the Moscow concert hall attack is a stark reminder of the need for heightened security measures and international efforts to combat terrorism.