A masked gunman was arrested shortly after he robbed a north Spokane bank Thursday, authorities say.

A Spokane police sergeant on his way home arrested the suspect, who investigators believe may be responsible for a series of armed robberies at Spokane banks that have ended with the gunman fleeing on a bicycle.

The suspect Thursday had a bike, wore a mask and reportedly displayed a gun, said Frank Harrill, FBI supervisory senior resident agent.

“It does appear consistent with one or more of the robberies,” Harrill said. “But it’s too early to make any other statement than that.”

The police sergeant pulled his patrol car in front of the suspect after he spotted him riding a bicycle on West Holyoke Avenue near West Bruce Avenue. A gun flew across the sidewalk after the suspect struck the patrol car and fell to the ground, police said.

Police say the man robbed the Washington Trust Bank, 1906 W. Francis Ave., just before 4 p.m.