Helicopters and marine units scoured the surface of the Patapsco River Monday after authorities received a report that an adult threw a child off the Francis Scott Key Bridge.

Police received a 911 call shortly before 11 p.m. and rescue workers from several agencies quickly searched the waters near Baltimore's outer harbor, Maryland Transportation Authority police spokesman Cpl. Jonathan Green said. Green did not say how long the search continued Sunday night, but it was resumed after dawn Monday.

Authorities found no physical evidence confirming the report, but they were taking it seriously, Green said.

"At this point, we're treating it as a credible report," Green said. "As long as there's any question that this happened, then we need to make every effort to investigate the matter fully."

Green said police were interviewing a person of interest, but he declined to provide additional details about who made the initial report, the age of the child, or the relationship between the child and the person being questioned.

Authorities issued an appeal for motorists on the Key Bridge between 8:30 p.m. and 10:30 p.m. to contact transportation police if they saw anything unusual or suspicious.

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