Talk with Times reporter Hector Becerra at 9 a.m. about the latest in the FBI’s investigation of state Sen. Ronald S. Calderon (D-Montebello) that this month saw subpoenas served to the Central Basin Municipal Water District.

One subpoena sought documents related to a groundwater storage plan that was the subject of long-running legal battle in southeast Los Angeles County.

Investigators also are seeking personnel records for the water district's former general manager, Art Aguilar, and two elected directors, Art Chacon and Robert Apodaca.

INTERACTIVE: Calderon family's connections 

The subpoenas, obtained by The Times, come two months after federal agents first requested records from Central Basin, including contracts connected to the senator's brother, Tom Calderon, a former state assemblyman and once-powerful advisor to the water district.

The subpoena seeking information on the groundwater storage effort for Southeast L.A. focuses on records connected to the project's environmental impact report, as well as to several engineering and consulting companies.

The companies named in the subpoena include HDR Engineering Inc., Willdan Financial Services, Pacifica Services Inc. and the Calderon Group, a consulting firm owned by Tom Calderon.

The FBI has been silent on its broader investigation of Sen. Calderon.

A law enforcement source told The Times that it involved Calderon's "income stream," and several state legislators have received subpoenas to appear before a grand jury. FBI agents also have questioned officials from several cities served by Central Basin.