They stress police are allowed to lie as long as they don't violate a suspect's rights to remain silent and speak to an attorney, and that detectives don't need a warrant to conduct "trash rips" - operations in which they seize a suspect's trash from outside his home.

http://www.hometownglenburnie.com/news/Top_Stories/2010/05/01-27/Police+may+use+trash+to+get+a+suspect%26%2339;s+DNA%0A.html

"Fourth Amendment protection does not extend to property that is abandoned or voluntarily discarded, because any expectation of privacy in the item searched is discarded upon abandonment," she said.