"The gunman acted alone, he prepared for this alone. There are no runaway shooters… He was preparing for this since January 2017," the source with a local law enforcement agency said.
Meanwhile, two teenage girls hurt in the shooting will be flown to Moscow soon to continue their treatment, regional authorities said Saturday.
"Medical specialists from Moscow flew to Crimea to consult those injured and determine their treatment plan… They decided to send two female patients… to Moscow clinics," the Crimean government said in a statement.
Some of the critically injured were airlifted to Moscow on Wednesday after a bomb and gun attack on the vocational school for teenagers in the city of Kerch.
Shooting in Kerch
The fourth-year student, identified as Vladislav Roslyakov, killed 21 people and wounded over 50 others in a bomb and gun attack that started inside the canteen at Kerch Polytechnic College.
The shooting was initially treated as a terrorist attack but was later reclassified as a mass murder. The gunman killed himself inside the college library. More than 40 victims remain in hospital, three of them in critical condition.