CHICAGO (CBS) — The Des Plaines Police Department could be facing a federal investigation into the disappearance of two semi-automatic rifles.

WBBM Newsradio’s Julie Mann reports Des Plaines Police Chief William Kushner admitted he doesn’t know where the two M-16A1 rifles are.

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The weapons were given to the department in 2002 as part of a federal program to equip law enforcement agencies with military surplus, and help combat terrorism and drugs.

However, an internal audit required by the Defense Department failed to locate them earlier this year.

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Kushner, who took over as chief two years ago, told the Daily Herald poor bookkeeping and widespread access to the armory likely are to blame for the guns’ disappearance.

He said bookkeeping was virtually nonexistent after 2007, but he has since fixed those problems by adding more internal security, limiting who can access the armory.

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However, Kushner anticipated the Law Enforcement Support Office and Defense Logistics Agency, which manages he surplus property program, would be taking a closer look into the missing weapons, and Des Plaines could be barred from participating in the program as a result.