The officer shot one person in the car lot of the casino after he allegedly jumped into the detective's vehicle.
His injuries are believed to be non-life threatening.
The officer was with his family unloading packages when the suspect allegedly got in.
He was warned to get out but when the suspect reached under the seat, the officer shot him, Fox5 reports.
Police say the suspect then ran away but was detained by hotel security and then taken to University Medical Center for treatment.
The officer was not injured in the incident.
Police were called to the scene in Nevada.
It is the second shooting at the casino and hotel in the past eight months.
In December, a gunman shot dead a woman in the lobby before turning the gun on himself.