Police have arrested four men, one of them a New York City police officer, in connection with an attack in Roosevelt Sunday.

Police say brothers Jose and Persio Vargas, Persio's son and NYC Police Officer Juan Nunez, who was off-duty, took part in the brutal beating Sunday.

The victim is identified as 52-year-old Darrell Jackson, a black man. Investigators say the Hispanic suspects warned Jackson to move away from the front of the Midway Deli on Nassau Boulevard, where the brothers work. When Jackson refused, an eyewitness says the suspects launched their vicious attack.

Dave Tillery, of Freeport, says he saw the men beating Jackson in the middle of the street. He says they had two baseball bats and were yelling racial slurs at the victim.

Tillery, a school security guard, says he pulled up and told the men to get off of him. He says he thinks his uniform scared off the attackers.

Jackson is listed in stable condition at Nassau University Medical Center.

Nunez, 32, of Freeport, pleaded not guilty to assault at his arraignment in Hempstead Monday, where his bail was set at $20,000. The NYPD has suspended Nunez, a police officer since 2001, from his post at the 101st Precinct in Queens.

Nassau County Police Commissioner Lawrence Mulvey says detectives have determined the attack was not motivated by racial bias. According to Mulvey, the four men wanted Jackson to leave the front of the store.

"In order to charge a hate crime, the motivation behind it is you select that victim because of his ethnicity, because of his or her religion, his or her sexual orientation and then you commit the crime," Mulvey says.

Police say the four men are currently being charged with assault, but could be charged with hate crimes as the investigation continues. According to police, they may also make additional arrests.

AP wire services contributed to this report

Beating reported in Roosevelt