For the second time in less than a week, the Chicago office of the Council on American-Islamic Relations is calling for a federal hate crime investigation of an attack on a suburban house of worship.

On Friday evening, police were called to the Muslim Education Center in Morton Grove, Ill. after a security guard heard projectiles whiz by and strike an outer wall of the facility where more than 500 people were praying. David Conrad, a neighbor with a history of conflicts with the center, was arrested and a high-velocity air rifle was seized from his property.

On Sunday night, a 7-Up bottle filled with acid and other unspecified chemicals was hurled at the College Preparatory School of America, an Islamic school in Lombard, where evening Ramadan prayers were underway, CBS Chicago reports.

Lombard Deputy Chief Pat Rollins described the device as a homemade "MacGyver bomb," a combination of household chemicals that makes a loud sound when it interacts with aluminum foil, he told the Chicago Tribune. "It will scare you," Rollins said, but usually doesn't cause a fire.

"These and other incidents of anti-Muslim bigotry are occurring in an atmosphere of hate resulting from inflammatory statements by elected officials nationwide," CAIR-Chicago Executive Director Ahmed Rehab said in a statement. The organization issued a community safety advisory for American mosques last week after the shooting at a Sikh temple in nearby Milwaukee and similar threats in at Missouri and Rhode Island mosques.

Both Illinois incidents came days after U.S. Rep. Joe Walsh (R-Ill.) warned that there is "a radical strain of Islam in this country...trying to kill Americans every week" at a town hall meeting in suburban Elk Grove Village.

Conrad's bail was set at $45,000 Monday for the shots that struck the Morton Grove education center, the Chicago Sun-Times reports. The judge also ordered Conrad to surrender any other guns and avoid contact with the mosque or its members.

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