That's true but I think there's much more to this story. The FBI is involved and there is/was a grand jury investigation. MG tried to subpoena the FBI to get copies of the surveillance videos and was basically told to "go pound sand."
http://www.nbc11.com/news/2635833/detail.html ...McAllister suggested that Brocchini tried to get Scott Peterson fired from his fertilizer sales job, which the detective denied.
Brocchini said he worked with the company to review expenditures Scott Peterson made to see whether they were work related. Investigators studied both personal and business spending -- some records of which had been subpoenaed by a the FBI, using a federal grand jury.
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Investigators studied both personal and business spending -- some records of which had been subpoenaed by a the FBI, using a federal grand jury. I have the feeling that the "Federal" in all of this relates to the bank and the fact that it's federally regulated. Therefore, a federal subpoena was necessary and MPD relied on the feds to get said subpoena for the financial records.