escapes from the police while committed to their charge under this Act;

without permission of the superintendent, leaves a welfare home in which he is required to reside in accordance with section 3 or to which he has been admitted on his own application under section 5; or

having obtained such permission left a welfare home for a limited time or for a specified purpose, fails to return at the expiration of such time or when such purpose has been accomplished or found to be impracticable,