In Florida v. Jardines, 133 S.Ct. 1409 (2013), the United States Supreme Court held that a dog-sniff on the defendant's front porch was a search unsupported by probable cause, and thereby affirmed the trial court's decision to suppress the evidence. http://www.supremecourt.gov/opinions/12pdf/11-564_5426.pdf
However, in U.S. v. Gutierrez, No. 14-1159 (July 29, 2014), the dog-sniff search was upheld as the police based their actions on good faith reliance on existing case law, and the search occurred before the Jardines decision came down.