A protester arrested for attacking two NYPD lieutenants on the Brooklyn Bridge is a CUNY graduate student who pulled one of the cops away from a crowd just before he was punched in the face, prosecutors said Friday.

Jarrod Shanahan, 29, who also teaches at the school, was allegedly part of a crew of seven agitators that assaulted the cops on Dec. 13 to stop them from arresting CUNY Professor Eric Linsker for allegedly throwing metal garbage cans at officers.

He was originally called “Male Suspect No. 2” as police hunted down the rowdies.

The grad student “hip-checked or otherwise shoved” Officer Patrick Sullivan during the scuffle and isolated Officer Philip Chan from the crowd — just before the cop was punched by another protester, prosecutors said.

They charged that even if Shanahan didn’t throw the punch that broke Chan’s nose, he wore a ski mask to obscure his face and separated Chan from the rest of the crowd.

“Whether or not he threw the punch, he’s liable for the punch,” the DA’s office said.

The activist’s lawyer, Jesse Berman, insisted the ski mask was just for keeping his client warm. “It’s cold this time of year and putting on a ski mask is not unusual,” he said.

Shanahan (pictured) remained silent in court.

His friends tried to post his $20,000 cash bail before a court lunch break but miscounted their bills.

They came back when the bail office was already closed — leaving the student in custody.

Meanwhile, cops said friday they had busted a man for phoning in threats to the NYPD, saying he was “dying to kill police,” cops said Friday.

Rayshawn Dixon, 28, was charged with making terrorist threats on Tuesday morning after sources said he called 911 shortly before 5 a.m.