(1)    A county having a population of 750,000 or more shall provide, as part of its county jail, for the confinement of all persons arrested for violation of state laws or municipal ordinances or otherwise detained by police officers of a 1st class city located within the county. A contribution toward the construction and equipment of the county jail from a 1st class city accepted by a county having a population of 750,000 or more under an intergovernmental cooperation agreement under s. 66.0301 is made for a municipal purpose, and a 1st class city may borrow money under ch. 67, appropriate funds and levy taxes for that purpose.

   (2)   Prisoners confined in the county jail under sub. (1) are in the legal custody of the county sheriff or other keeper of the jail. The sheriff or other keeper is legally responsible for any such prisoner’s confinement; maintenance; care, including medical and hospital care; release prior to an initial appearance in court; and the initial appearance before the circuit court or the initial appearance before a municipal court at a location within the county jail.

   (3)   Except as provided in sub. (4) and ss. 302.33 (2) and 302.38, a county under sub. (1) is solely responsible for:

      (a)    The costs of operating and maintaining the county jail and maintaining the prisoners in the county jail.

      (b)    The costs of carrying out its legal responsibilities under sub. (2).

   (4)   An intergovernmental cooperation agreement under s. 66.0301 between a city and a county under sub. (1) may provide for the city to reimburse the county for its cost of custody at the initial appearance before a municipal court located within the county jail for prisoners who are in custody exclusively for violation of a municipal ordinance.