Mankato (KMKO)-As law enforcement officials continue efforts to find those responsible for vandalizing a sculpture in downtown Mankato, the reward has been increased.  $2,000 is offered for information leading to the arrest and conviction of the person who damaged the sculpture at Second and Main Streets.  The top part of the bronze and stone art work was broken recently.  The sculpture created by Susan J. Geissler is worth $26,000.  Donations from the artist and the City Center Partnership contributed to the increased reward.  The fund is also sponsored by the cities of Mankato and North Mankato.  If you have information that could help in the case, call 387-8780.