A Massachusetts police officer may stop and frisk a person for weapons, if the officer reasonably suspects that the person may be armed and dangerous.
According to the Supreme Judicial Court,
the police officer’s action [in making such a stop, must] be based on specific and articulable facts and the specific reasonable inferences that follow from such facts in light of the officer’s experience.Commonwealth v. Silva, 366 Mass. 402 (1974)
While the officer need not be absolutely certain that the individual is armed, the basis for this acts must lie in a reasonable belief (gained through specific and articulable facts) that his safety or that of others is at stake.Id. at 408
The sole purpose of a stop-and-frisk search is to detect concealed weapons and the scope of the officer’s search cannot go beyond those limits.