The A in the circle is an anarchist symbol, it stands for anarchy, not Antifa. But it is likely Antifa or another Communist group behind it.
Via Free Beacon:
A banner reading “more dead cops” was found Sunday afternoon hanging from an overpass on Route 9 near Albany, N.Y.
The banner was taken down around 5:10 p.m. Sunday after the police received a call, local media reported.
“They put the sign on the overpass, but it’s insignificant. The police are resilient,” Retired Police Cpt. John Cooney said.
The banner included a symbol–an “A” with a circle around it–much like those used during recent antifa Riots in Berkley, Ca.