A total of 14 inmates of a government-run juvenile observation home for boys in Mathura, escaped after breaking the rusted iron grills of a window.
The incident took place about 'two hours past midnight' on Thursday.
This is the second such incident this year.
While police managed to trace nine of them, five are still on the run.
The 14 minors -- charged with murder, sexual assault and gang rape -- were from Mathura, Aligarh and Hathras.
Mathura SP Gaurav Grover said, "With spoons and other tools, the boys had loosened the bolts that fastened the window in place over some time. After they removed the grill and escaped."
The wall of the juvenile home is not too high and the role of the guards is under investigation.
Six people, including three staff members at the observation home and three home guards, have been booked under sections 222 (intentional omission to apprehend on the part of public servant bound to apprehend person under sentence or lawfully committed) and 223 (escape from confinement or custody negligently suffered by public servant) of the Indian Penal Code on the basis of a complaint filed by district probation officer.
"A team has been formed to track down the five others," Grover said.
In March this year, five juveniles had escaped after a scuffle with the guard. They were apprehended and brought back later.
Police said a few days ago, inmates at the home had staged a protest against the decision to move out two boys, who had turned 18, to the district jail.
The number of inmates at the observation home is 106 which is three times more than its capacity of 30 inmates.