fired. The caller reported eight shots fired “possibly” two blocks south of 14th and Hull Streets, a high-crime area in which “drug activity as well as random gunfire” were “usual[ ].” J.A. 46, 77. The caller said nothing more; in particular, he or she included no description of a suspect.
Officers Stephen Gaines and Eric Fries responded to the call and arrived at 14th and Hull at 10:48 p.m. They split up and patrolled the area in marked police cars. Fries soon saw four young black men, including appellant Massenburg, walking north at the corner of East 17th Street and Stockton Street, four blocks west and two south of the intersection of 14th and Hull and thus four blocks from the alleged origin of the shots. They were walking in the direction of Fries’s marked car and did not stop or change course when they saw it.
Fries approached in his vehicle and asked, “hey guys, can you stop for a second?” J.A. 31. The men stopped to talk with him. Fries asked if they had heard gunfire, and one man reported hearing shots fired from a vehicle on Maury Street, two blocks south of their present location. Gaines arrived, the two officers exited their vehicles, and they began taking the men’s names. Fries then asked if they had weapons on them and if they would consent to a pat-down. The four men were now “all basically lined up in a row on the sidewalk,” with the man who reported hearing gunfire on Maury Street on the left end of the line and Massenburg on the right. J.A. 32. According to Gaines, the three left-most men were “pretty much shoulder-to-shoulder, and [Massenburg] was kind of offset from the group” by a “foot or two,” “give or take.” J.A. 57.
The man on the left consented to Fries’s request for a pat-down, as did the man nearest him. Gaines began at the other end of the line, asking Massenburg if he would consent to a frisk. Gaines testified that Massenburg, in reply to the request, “was kind of hesitant and stand-offish, and kind of real reluctant to give consent to a pat down or a search of his person.” J.A. 48. Instead, “[h]e stated he did not have anything. You don’t need to check me. Stood back and kind of air-patted himself down, stating, trying to show he didn’t have anything.” J.A. 48. At this point Gaines insisted and patted Massenburg down without his consent.
Officer Fries testified that he had seen “a small bulge in the left jacket pocket of Mr. Massenburg” prior to Officer Gaines’s frisk, but he “didn’t alert” Gaines to it. J.A. 32, 42. Officer Gaines, asked multiple times about the basis for his suspicion of Massenburg, never indicated in his testimony that he saw a sign or signal from Fries.
During the frisk of Massenburg, Gaines felt the handle of a firearm on Massenburg’s waist band (not in the jacket), and Massenburg fled before Gaines could grab it. Gaines pursued and directed him to drop the firearm, which Massenburg did, dropping it on the grass. Massenburg ran another 250 feet before Gaines caught up and arrested him. In addition to the firearm, police recovered a small amount of marijuana on Massenburg’s person.
B.
Massenburg was charged with one count of possession of a firearm by a drug user, in violation of 18 U.S.C. § 922(g)(3), and one count of possession of marijuana, in violation of 21 U.S.C. § 844. He filed a motion to suppress the firearm and marijuana, arguing that Gaines lacked the reasonable, particularized suspicion that he was engaged in criminal activity necessary to authorize a nonconsensual frisk under the Fourth and Fourteenth Amendments.