After the Capitol riot, Clearview AI, a facial-recognition app used by law enforcement, has seen a spike in use, said the company’s chief executive, Hoan Ton-That.

“There was a 26 percent increase of searches over our usual weekday search volume,” Mr. Ton-That said.

There are ample online photos and videos of rioters, many unmasked, breaching the Capitol. The F.B.I. has posted the faces of dozens of them and has requested assistance identifying them. Local police departments around the country are answering their call.

“We are poring over whatever images or videos are available from whatever sites we can get our hands on,” said Armando Aguilar, assistant chief at the Miami Police Department, who oversees investigations.