Three police officers from Bangladesh have already reached Riyadh, it said on Tuesday in a statement.
It said necessary procedures to repatriate him had been completed in collaboration with the home ministry, Police Headquarters, and Bangladesh mission in Saudi Arabia.
The government “deeply” appreciated the kingdom for extending cooperation.
Kamrul fled there after allegedly torturing 13-year-old Rajan to death at Kumargaon on July 8.
As the video of the savage act went viral, expatriate Bangladeshis spotted and detained him with the help of Bangladesh Consulate General in Jeddah.
He was handed over to Saudi police on July 13.
Police submitted chargesheet naming 13 on Aug 16 as the trial in the case was going on in a Sylhet court.
Ten of the accused have been arrested, including Kamrul’s brothers Ali Haider and Muhit Alam.
His other brother Shamim Ahmed is among the three fugitives.
Police Headquarters' Additional Superintendent Mahabubul Karim, Sylhet Metropolitan Police’s Additional Commissioner Mohammad Rahmat Ullah and Assistant Commissioner AFF Nezam Uddin had left for kingdom early on Monday to bring Kamrul back.