HOUSTON – Houston Police Chief Art Acevedo revealed new details about what happened that led an FBI agent to shoot a kidnapping victim in northeast Houston last week.

The agents were sent to the home to rescue 47-year-old Ulises Villadares early Thursday morning.

Two agents went to the back of the house where they believed the victim was being held. They used a breaching tool to break a window as other agents entered the front of the house.

“As one agent was breaching the window, unfortunately he lost control of the breaching tool and it fell into the residence,” Acevedo said.

The agent who fired the fatal shot started using his M-4 rifle to break the window, Acevedo said

“Tragically and sadly, Mr. Villadares was right by that window and he was bound and had his hands in front of him,” Acevedo said. “He actually grabbed at the rifle and started to pull the rifle.”

As the victim and agent struggled over the rifle, the agent – apparently not realizing it was the victim – fired two shots. One of the bullets struck and killed Villadares.

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Acevedo said they don't know why Valladares was pulling on the FBI agent's weapon but may have been trying to get out of the house. The chief added that agents were yelling "FBI" the entire time but said it was very dark inside the room.

"It's a tragedy that we can't take back," the chief said.

The chief said he will not comment on FBI’s decision to use weapon to break the window, but adds HPD protocol would not call for that.

The chief said they are working closely with the FBI on the investigation. He explained that they were focused on the criminal aspect, while the FBI was concentrating on the administrative part.

When completed, they will present it to Harris County District Attorney Kim Ogg, and then she will make determination as to whether or not it will go to grand jury or U.S. Attorney’s Office.

Villadares was abducted from his Conroe home by two men who said his brother, who also lived at the home, owed them money.

Two suspects were later arrested at a Webster hotel and that's when police learned where Villadares was being held.