VALLEJO -- A pedestrian was struck by a pickup truck Monday night while crossing a busy Vallejo street after flagging police down to report a crime, police said.

Police said the victim flagged down an officer about 7 p.m. on Sonoma Boulevard and Louisiana Street to report that a person was brandishing a gun from a blue Scion, police said. Police dispatchers also received two separate reports on the same issue around the same time, police added.

As the victim was talking to the officer, the reported blue Scion drove by and soon was followed by the officer, police said.

As the officer pulled the Scion over and searched the driver and car, the victim jaywalked across Sonoma Boulevard while "extending his arm" to stop cars, police said.

The driver of a red Dodge pickup truck traveling north on Sonoma Boulevard did not see the victim in time and struck him, police said.

The victim was airlifted to John Muir Medical Center in Walnut Creek with head injuries and possible internal injuries, Vallejo fire officials said.

Police found no gun in the blue Scion or on the driver, and the pickup truck's driver was not cited.