Answer to Question 1
The Garner decision declared unconstitutional a Tennessee statute that authorized police officers who give notice of the intent to arrest to use all the necessary means to effect the arrest if the suspect flees or resists.
Four years after Garner, the Supreme Court decided the landmark case of Graham v. Connor, 490 U.S. 386 (1989), which set the standard for non-deadly force. The Court declared emphatically that all claims involving allegations of excessive force against police officers must be analyzed under the Fourth Amendment's reasonableness requirement. Further, the Court adopted a test of objective reasonableness to decide when excessive force is used. This requires focusing on what a reasonable police officer would do without regard to the officer's underlying intent or motivation.
Answer to Question 2
The methods used to spy on criminal suspects are quite diverse and include wiretapping, bugging, hacking into computer transmissions, tracking movements of persons and equipment, video surveillance, and seeing through opaque surfaces using devices such as thermal imagers and gun detectors. The use of racking devices is governed by Supreme Court decisions. The requirements are similar to all electronic surveillance equipment in which probable cause and a warrant are necessary.