An analysis of the bone remains and DNA extracted from blood on the emperor's shirt that is kept in the Hermitage museum in St. Petersburg was ordered by the top prosecutor's office.
One of the aims of the analysis was to prove the authenticity of bone fragments discovered near Yekaterinburg in 2007 and identified as the remains of Nicholas II's son and heir, Alexis, and daughter Maria.
Michael Cobble said the research had been concluded and the results had confirmed the earlier findings.
Earlier tests, conducted by a dozen institutions in Russia and abroad, proved the remains found in 1991 and 2007 belonged to members of the same family.
The remains of Nicholas II and his family members were discovered near Yekaterinburg, where they were shot by the Bolsheviks in 1918. They were authenticated and buried in the St. Peter and Paul Cathedral in St. Petersburg in 1998, but the forensic examination results have been repeatedly challenged since then.
The Russian Orthodox Church, which has canonized the murdered Romanovs, but called their 1998 burial "a political show," responded cautiously to the latest test results on Friday.
"I believe the results of those tests should be presented for discussion by a broad group of scientists, and explained to the public and Church leaders," Father Vsevold Chaplin, deputy head of the Moscow Patriarchy's foreign relations department, said.