Chicago ? Prosecutors are investigating allegations that six off-duty Chicago cops were caught on a downtown bar’s video camera beating four businessmen, the second such incident in recent months, law enforcement sources said.

In the Dec. 15 beating at the Jefferson Tap and Grille, one alleged victim required reconstructive surgery on his face and another suffered four broken ribs, said Sally Saltzberg, a lawyer for the men.

Other bar patrons called 911. But when patrol officers responded, the off-duty officers involved allegedly spoke to them and the patrol officers left without intervening, sources said.

Security cameras inside and outside the bar recorded most of the beating, said Saltzberg, who said she has not seen the tape herself.

Law enforcement sources have described the content of the video to the Chicago Tribune.

The Cook County state’s attorney’s office is considering criminal charges against the officers, sources said.

Saltzberg said the four men beaten at Jefferson Tap are frustrated that, given the existence of the video, no formal action has yet been taken.

Details of the incident have emerged in the wake of accusations that Chicago police officer Anthony Abbate beat a woman Feb. 19 at a Northwest Side bar. The incident also was caught on the bar’s security video. Charges against Abbate, 38, were upgraded last week to felony aggravated battery, from a misdemeanor.