Comello's lawyer, Brian Neary, refused to discuss the written phrases and said only that "handcuffs" were on his client's hand, NBC New York reported.
Another lawyer representing Comello, Robert Gottlieb, did not respond to messages seeking comment, the station reported.
Wearing green-and-white striped clothing, Comello showed his hand to the news media while sitting in the courtroom's jury box, according to NBC New York.
Comello, of Staten Island, was arrested Saturday in Brick, New Jersey.
Speaking to reporters on Saturday, New York Police Department Chief of Detectives Dermot Shea declined to say if Comello and Cali knew each other, saying that authorities were investigating a potential relationship.
Nor would Shea say if Comello had targeted Cali.
Before Comello's arrest, Shea said it appeared a gunman may have lured Cali to his death after deliberately backing into Cali's SUV with a pickup truck. When Cali stepped outside his home to investigate, a man fatally shot him six times.
After the arrest, Gottlieb said that the "people who know [Comello] best, his family and friends, cannot believe what they are hearing. There is something very wrong here and we will get to the bottom of it.”
Tim Stelloh is a reporter for NBC News, based in California.