The Chronicle, in a court filing Monday, argued that federal prosecutors failed to pursue alternative sources of information about the source of the leak of grand jury transcripts to reporters Mark Fainaru-Wada and Lance Williams, who now face jail if they don’t reveal their source. The Justice Department says it issues subpoenas to journalists only as a last resort. The Chronicle contends the same standard is part of the constitutional guarantee of freedom of the press and was not met in this case. The filing comes in the Chron’s appeal of an 18-month prison sentence handed down by U.S. District Judge Jeffrey White. The imprisonment and possible fines have been delayed until the appeals court reviews White’s decision. (The photo was taken by Darryl Bush of the Chron. In it, Williams, center left, and Fainaru-Wada, center, speak to reporters after leaving court Sept. 21.)