Ogden police have booked two teenage boys into a juvenile detention facility, bringing to four the number of people arrested in an investigation into robberies of two Ogden banks and a gas station.

The two, arrested Friday, joined a 16-year-old girl who was referred to juvenile court Thursday for allegedly aiding in a robbery at the Golden West Credit Union earlier that same day.A fourth defendant, Roger M. Phillips, 21, of Ogden, was arraigned in federal court late Friday in the robbery of Golden West. He was turned over to U.S. marshals in Salt Lake City pending a Monday detention hearing before U.S. Magistrate Ronald Boyce.

Police say they also are investigating whether Phillips is linked to the robbery of Mountain America Credit Union on Feb. 5 and a Chevron station on Tuesday.

The Weber County attorney's office said it elected not to file a charge in the Chevron case at this time because federal prosecutors pushed ahead with the bank robbery charge.

Ogden Police Capt. Marlin Balls said the two male juveniles were arrested by Detective David Lucas late Friday morning on suspicion of conspiracy to commit bank robbery.

Balls said the two helped in planning both bank robberies in which police said they believe Phillips was involved.