A tense hostage drama in the basement of a jewelry store ended peacefully on Wednesday night when a man claiming to have a grenade surrendered after holding the store’s owner hostage for hours, the police reportedly said.

The man talked with deputy chief John Sheyka, a hostage negotiator for the Jersey City Police Department, through a crack in a door blocked with furniture in the basement of A&E Jewelry, at 57 Sip Avenue, The New York Times reports. Around 6 p.m., he released the owner, whose identity was not released. The owner was taken to the Jersey City Medical Center to be treated for minor injuries, according to a spokesman for Mayor Jerramiah T. Healy.

During the failed robbery attempt, the owner’s wife was beaten in the street by a second man who escaped on foot running from Journal Square. The woman’s condition was not known Wednesday night.

Around 8:40 p.m., Sheyka reportedly told the man that Diamond, a German shepherd dog, was going to be sent into the room.

Officers took the dog to the basement door, and the man surrendered. The man said that he could kill a police officer, but could not hurt a dog, police chief Robert Troy reportedly said.

According to Jersey City officials, the man had a knife, a fake hand grenade and a fake handgun.

Chief Troy said later that he had bluffed, and would never have jeopardized the dog. “Thank God it worked,” he reportedly said.

JCK