GULF SHORES, Ala. -- A car drove into a crowd of people at a Mardi Gras parade in Alabama on Tuesday, injuring 12 members of a local high school marching band.

CBS affiliate WKRG reports that an SUV representing the Military Officers Association of America crashed into the crowd before the start of the Gulf Shores Parade. Grant Brown, a spokesman for the city, said in a press conference that the driver was a 73-year-old man who the MOAA says is a member of a local chapter. He is in police custody, although there is no indication the crash was anything other than what Brown called a “horrific accident.”

Three of the students were in critical condition, down from four earlier in the day, officials told WKRG, and one was transported by helicopter to a hospital in Mobile. Officials told WKRG that the victims ranged in age from 12 to 17. Some victims were reportedly under the car when it came to a stop.

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Eddie Tyler, superintendent of Baldwin County Public Schools, told CBS News that six of those injured in “this unthinkable accident” were middle school students and six were high school students.

Video from the scene shows paramedics and emergency workers tending to several victims lying on the street:

“A teenage band has just started to march down the parade route when they were struck from behind. The vehicle was apart of the parade,” spokesman Grant Brown told WKRG. The driver was reportedly an elderly man.

A representative for Gulf Shores High School told CBS News that school was out of session for Mardi Gras on Monday and Tuesday. There are about 30 to 40 students in the band, but the school does not have further information about the number of students who were injured in the crash.

The city of Gulf Shores released a statement on its Facebook page shortly after the incident: