Thieves steal parts from three Miami Police Marine Patrol boats.

Cops say someone broke into their boats and removed their lower units, which include the transmission and propellers. A police spokesman says whoever is responsible may try to sell the parts.

The parts are worth about $18,000 in total.

Police plan on checking surveillance video from the Miami Yacht Club, where the boats were docked.

If you have any information, call Miami-Dade Crimestoppers at 305-471-TIPS.