What factors must be considered in determining whether a search and frisking of a defendant is reasonable under the Fourth Amendment?

Here, Officer Harshbarger knew that the apartment complex was an area with a high level of drug activity. (See People v. Souza (1994) 9 Cal.4th 224, 240 ["An area's reputation for criminal activity is an appropriate consideration in assessing whether an investigative detention is reasonable under the Fourth Amendment"].) He also knew that, upon seeing agents and officers wearing "police" raid vests, defendant pulled a plastic baggie out of his pocket and threw the object away. Based upon his training and experience, Harshbarger reasonably believed that defendant was trying to dispose of illicit drugs. And, before the frisking, Harshbarger knew that defendant had been recently discharged on parole. In addition, it was 7:55 p.m. in October (id. at p. 241 ["time of night is another pertinent factor in assessing the validity of a detention"]), and defendant was wearing baggy clothing that could easily conceal a gun or other weapon.