Carolina Lopez, 19, was ordered held without bond Monday after a court appearance to face second-degree murder charges.
Police say Lopez and boyfriend Reynaldo Munoz, 20, were trying to steal the watercraft from the North Bayshore Drive home of attorney Jeffrey Davis around 2:30 p.m. Saturday.
Munoz made his way to the backyard, where he used an extension cord to lower the wave runner into the water, but he was confronted by Davis' wife and teenage son, who were home at the time, police said.
According to police, Munoz threatened the pair and claimed he was armed. Miami-Dade Police say an unidentified juvenile armed with a shotgun shot Munoz, killing him at the scene.
Police are trying to determine whether the shooting was justified.