BIRMINGHAM, Ala. (AP) — Federal authorities say four people have been indicted in what they describe as a conspiracy to use a fake bomb to rob a bank in Alabama.

An indictment made public Monday says two people planted a hoax bomb outside an elementary school in the Birmingham suburb of Trussville in November, and one called 911 claiming to have seen someone leave the explosive.

Prosecutors say the goal was to draw police to the school so they could then rob a bank. Two others acted as lookouts.

But the alleged scheme fell apart because a police officer appeared to be near the bank after the call.

The supposed bomb was made of modeling clay, wires and other harmless materials.

Authorities say the four are charged with bank robbery conspiracy.