A New Hope borough police officer who shot a man tussling with another cop in a holding cell in March thought he was deploying his Taser when he fired his handgun, the Bucks County district attorney found.

The unnamed officer will not face any criminal charges because of his “honest but mistaken” belief he was deploying his Taser at the time he discharged his service weapon, District Attorney Matthew Weintraub said in a news release Friday.

“After careful consideration, I have determined that (the officer’s) shooting of arrestee Brian Riling on March 3, 2019, was neither justified, nor criminal, but was excused,” Weintraub wrote in a letter to New Hope Police Chief Michael Cummings.

Riling, 38, of Pipersville, was treated in critical condition for his wound then released, and faces prosecution in two separate criminal cases.

Weintraub is following protocol and not releasing the officer’s name because he is not being charged, he said in a news release. After the shooting, the officer was put on paid administrative leave until his retirement on Wednesday.

The district attorney’s investigation included an extensive review of police reports and video footage of the actual shooting, which Weintraub’s office released to the public Friday.

The officer would have been justified to use his Taser to get Riling under control as he scuffled with another cop, who may have been in danger, Weintraub wrote in his letter. But the use of a firearm should be an officer’s last resort and it was not justified in this case, he said.

Since the cop believed he was drawing his Taser, and not his firearm, he did not “possess the criminal mental state required to be guilty of a crime under state law,” Weintraub wrote.

While the officer’s placement of his Taser on his right side, in front of his firearm, violated a department policy that stipulates Tasers should be worn on an officer’s non-dominant side, it does not constitute a violation of the law, the release states.

The video shows Riling -- described by authorities as a fit 6-foot-4-inch, 240-pound construction worker -- enter the police holding cell and remove his belt at the direction of another officer. When he takes off his belt, what appears to be a drug baggie falls from his waistband to the floor and Riling steps on it, the footage shows.

When the officer tries to move Riling off the object, a struggle ensues between the pair and Riling chucks the baggie into the cell’s toilet. The officer who later shot Riling then comes into the cell to help the other cop, who is wrestling with Riling on a bench inside the cell.

“With his service firearm in his hand, the second officer yells ‘Taser!’ before shooting Riling in the torso,” the news release states. “Riling then falls to the ground and both officers leave the cell.”

The video shows Riling flushing the toilet as he slumps to the ground, the release states.

Following the shooting, Riling writhes on the floor of the cell pleading for help. He repeatedly asks why he was shot and begs for something to stop the pain.

“Oh my god. Please, please help. Dude, my kids, my kids, My daughters. Please, please, my daughters, please,” Riling begs as he moans. “Get me f---ing out of here. I don’t want to die. It hurts everywhere, guys.”

An officer crouches on the floor of the cell with him telling him to breathe, relax and promising that he will be fine.

“Dude, I don’t want to die,” Riling exclaims.

When an officer tells him he is not going to die, Riling shouts: “How do you know that? I’m dying now. Why would you f---ing shoot me? Are you kidding me?”

Riling was treated by other officers before he was taken to St. Mary Medical Center in Langhorne, where he was treated in critical condition for several days. He has since been released.

Riling was in police custody because he was arrested earlier on March 3 and charged with intimidation and retaliation against a victim, simple assault and related offenses. He also is charged with burglarizing the same victim’s home in mid-February.

Riling’s attorney Richard Fink was not in the office Friday afternoon and could not be reached immediately for comment on the prosecutor’s decision.

On March 3, Riling was arrested by New Hope police in the parking lot of his estranged girlfriend’s home after he’d spent the day stalking her and sending her more than 100 text messages, including ones that said he wanted her dead and threatened suicide, the Bucks County Courier Times reports, citing court documents. The woman reportedly told police Riling was outside of her home at 4 a.m., harassed her throughout the day and then waited for her to get done working at a local restaurant. Riling allegedly then confronted her, grabbed her by the throat and spit in her face.

Riling allegedly sent her text message after text message, including ones that demanded she drop the allegations stemming from the February incident.

“The officer who shot Riling was aware of these two criminal episodes ahead of the holding cell incident, and had himself heard threats of violence made by Riling during a phone call between Riling and the previously mentioned victim,” Friday’s news release states. “These details are not provided as proof of criminal behavior on Riling’s part, but to illustrate the mindset of the officer who shot him.”

This is the second officer-involved shooting for the 11-officer New Hope police department, the Courier Times reports. The first happened in September 2012 when police went to the home of a resident to serve an involuntary mental health commitment warrant.

Prior to last month’s shooting, the officer who fired his weapon had decades of exemplary service with the department, supporting by dozens of commendations and letters, the release states.

Sara K. Satullo may be reached at ssatullo@lehighvalleylive.com. Follow her on Twitter @sarasatullo and Facebook. Find lehighvalleylive.com on Facebook.