Bexar County Sheriff Susan Pamerleau believes Gilbert Flores, who was fatally shot by deputies near San Antonio, may have had a knife in his hand, citing video she saw of the incident. (Reuters)

Authorities in Texas say they believe a man fatally shot by sheriff’s deputies last week was holding a knife when he was killed, a shooting that was captured on video and is being investigated by the FBI.

Police had responded to a home in Bexar County, where San Antonio is located, after a report of a possible domestic disturbance on Friday morning. The Bexar County Sheriff’s Office said deputies tried to arrest Gilbert Flores, 41, but that he resisted and the officers opened fire.

A video released on Monday showed that Flores seemed to have at least one hand up when he was shot. In this footage, which was captured by a bystander and released by KSAT 12 News (warning: very graphic), Flores’s left arm is obscured by a telephone pole.

[Video appears to show Texas police shooting a man with his hand up]

Police say they have viewed a second video that shows both of Flores’s arms were raised when he was shot, adding that this other footage appears to show Flores holding a knife.

“We believe that Mr. Flores had a knife in his hand, and that video will help us have a better idea of exactly what he had in his hand,” Bexar County Sheriff Susan Pamerleau said at a news conference Wednesday.

While the sheriff’s office had previously described Flores as armed, they did not initially mention the type of weapon. The office said that the deputies who arrived Friday morning found a woman with a cut on her head and a baby that may have been injured. The two deputies involved in the shooting — Greg Vasquez and Robert Sanchez — remain on paid administrative leave while the investigation takes place.

Gilbert Flores in an undated photo. (Bexar County Sheriff’s Office via AP)

Investigators have submitted this second video to the Texas Department of Public Safety to see if it is possible to enlarge and slow down the footage to show what happened, she said.

“It covers a longer period of time prior to the shooting,” Pamerleau said. “It also shows it from a different angle.”

Nicholas LaHood, the district attorney for Bexar County, told CNN that the second video is a closer look at the shooting and offers “a better view to make an assessment on what happened.”

[Washington Post database: 666 people shot and killed by police as of Wednesday]

The FBI has opened a civil rights investigation into the shooting, according to Special Agent Michelle Lee.

“Experienced civil rights investigators from the FBI will thoroughly review the facts and circumstances surrounding the shooting,” Lee said in a statement. “Our focus is to determine whether a civil rights violation took place as a result of a deputy willfully engaging in the use of excessive or unjustified force.”

Lee also said the FBI is monitoring the sheriff’s investigation into the shooting.

The video released Monday by KSAT 12 News did not contain sound other than the gunshots, so it is not clear what was said or what occurred before the shots were fired. In a news conference last week, Pamerleau called the video “cause for concern,” before saying it was important to let the investigation run its course.

“If he has a deadly weapon in his hand that we can’t see, that’s a major factor in telling us that the officers were facing a deadly threat,” said David A. Harris, a law professor at the University of Pittsburgh and an expert in police use of force. “So we certainly want to know what was in his hand.”

However, Harris said that merely having a weapon doesn’t necessarily make someone a deadly threat.

“Even if he was armed, in the moment in which he is shot, there has to be the presence of a deadly threat,” he said. “With hands in the air, even if a weapon is present, with hands in the air and no physical motion, you have to ask where’s the deadly threat?”

Rep. Joaquin Castro (D-Tex.), who represents part of the San Antonio area, has called on the sheriff’s office to release the second video.

“The encounter is extremely disturbing as it appears to show an unarmed man with his hands up being shot by a deputy,” Castro said in a statement Tuesday, after the first video was released.

On Wednesday, Castro also questioned why authorities had not determined whether or not Flores had a knife or a weapon:

The sheriff’s office has sharply criticized KSAT 12 that released the first video of the shooting, calling it “sensational behavior” and asking people to call the news station to complain.

In a statement, the sheriff’s office said its deputies had received threats. A spokesman said he would not expand on the number of threats or the type, but said the office was taking precautions to keep deputies safe.

This shooting occurred amid an acutely charged backdrop. Over the last year, a protest movement across the country has decried how police officers use lethal force, with video recordings playing a role in pushing some deaths into the public consciousness. Meanwhile, police officers have said they are increasingly concerned about the tense atmosphere.

Fewer officers are shot and killed these days, but this anxiety has persisted due to ongoing protests, according to current and former law enforcement officers. Since last week, four different police officers have been killed, most recently a Texas deputy near Houston gunned down while getting gas and an Illinois officer shot north of Chicago. The latter shooting sparked a manhunt that continued Wednesday.

Related:

President Obama: Violence against police “is completely unacceptable”

The Washington Post’s database tracking people shot and killed by police

Thousands dead, few prosecuted. A look at the rarity of officers facing charges

The power of video in police shootings

Fewer police officers are being killed, but they describe increased tension