This lesson provides guidance for law enforcement officers on the following topics:

• When is a person in custody so that they must be given the Miranda warnings, and when is a Miranda waiver rendered involuntary?

• Does a warrant authorizing a blood draw for alcohol also permit testing the blood for other drugs?

• When does a dog sniff impermissibly prolong a traffic stop? And, what shows that a dog sniff is reliable?

• When does an officer have a duty to intervene to prevent another officer from using excessive force?

• If a car owner consents to the installation of a tracking device and then lets a suspect borrow the car, do law enforcement officers violate the suspect’s Fourth Amendment rights by tracking the suspect’s location while the suspect drives the car on public roads?