Neb. Rev. Stat. § 43-248

A peace officer may take a juvenile into temporary custody without a warrant or order of the court and proceed as provided in section 43-250 when: (1) A juvenile has violated a state law or municipal ordinance and such juvenile was eleven years of age or older at the time of the violation, and the officer has reasonable grounds to believe such juvenile committed such violation and was eleven years of age or older at the time of the violation; (2) The officer has reasonable grounds to believe that the juvenile has run away from his or her parent, guardian, or custodian; (3) A probation officer has reasonable cause to believe that a juvenile is in violation of probation and that the juvenile will attempt to leave the jurisdiction or place lives or property in danger; (4) The officer has reasonable grounds to believe the juvenile is truant from school; (5) The officer has reasonable grounds to believe the juvenile is immune from prosecution for prostitution under subsection (5) of section 28-801 ; (6) A juvenile is seriously endangered in his or her surroundings and immediate removal appears to be necessary for the juvenile's protection; (7) A juvenile has committed an act or engaged in behavior described in subdivision (1), (2), (3)(b), or (4) of section 43-247 and such juvenile was under eleven years of age at the time of such act or behavior, and the officer has reasonable cause to believe such juvenile committed such act or engaged in such behavior and was under eleven years of age at such time; or (8) The officer believes the juvenile to be mentally ill and dangerous as defined in section 71-908 and that the harm described in that section is likely to occur before proceedings may be instituted before the juvenile court.