An Army veteran-turned security guard has been hailed as a 'hero' after she died while trying to stop the Idaho mall gunman.
Jo Acker, 26, a transgender woman, was one of two victims shot dead when 27-year-old Jacob Bergquist opened fire at Boise Towne Square on Monday. Roberto Padilla Arguelles, 49 - who lived in Rupert, Idaho - also died at the scene.
Five others, including a police officer, were injured.
Gunman Bergquist died in the hospital today from injuries he sustained in a shootout with police.
The Boise Police Department (BPD) confirmed that Acker - who was a forward observer in the US Army for three years, according to her Facebook profile - died trying to stop the shooter.
Jo Acker (left and right), 26, was a transgender woman was working as a Boise Towne Square security guard when 27-year-old Jacob Bergquist fatally shot her after opening fire at the shopping center yesterday afternoon
Acker's sister Shawna Lee Lannigan (right with Acker, center) called her 'a hero' and wrote in a tribute post: 'I can’t even put into words how completely devastated and shattered I am'
Roberto Padilla Arguelles (not pictured), 49 - who lived in Rupert, Idaho - was another victim of the tragic shooting. He was pronounced dead at the hospital
Acker's sister Shawna Lee Lannigan called her 'a hero' and wrote in a tribute post: 'I can’t even put into words how completely devastated and shattered I am.'
'Jo you were always kind and loving…you always had such an enormous heart of gold. I always felt like your keeper I always wanted to protect you and you always wanted to protect others.'
Lannigan added: 'I love you to the ends of this earth and beyond. I will miss you until we meet again!'
Tiffany Luna, another sister, also paid tribute to Acker in a post calling her 'a hero (who) will be greatly missed'.
'Because of (Jo’s) heroics many lives were saved,' she added.
Coroner Dotti Owens said Bergquist's cause of death was still pending, according to The Washington Post.
Boise Police Chief Ryan Lee said at a news conference the shooting was reported about 1.50pm on Monday - as well as a report that one person was 'shot and down' at that time.
Ada County dispatch said that callers identified the shooter as a white male adult, dressed in black and in possession of guns, as reported by CBS 2.
The BPD explained in a statement on Tuesday: 'Evidence indicates the suspect was contacted by a security officer on the first floor of the building near a department store on the west side of the building.
'The suspect shot the security officer who died at the scene.'
The security guard was later identified as Acker, who joined the Army after high school and was a forward artillery observer and a paratrooper stationed in Florence, Italy, for two years.
Ray Dawn (right with Acker), Acker's partner of nearly three years, described her as 'one of the strangest, quirkiest individuals I’ve ever known' and added that she 'loved her family'
Acker joined the Army after high school and was a forward artillery observer and a paratrooper stationed in Florence, Italy, for two years
Acker was born in Seattle and grew up in Colorado Springs, Colorado, and Boise, Idaho.
Ray Dawn, Acker's partner of nearly three years, told the Idaho Statesman: 'She was confronting the suspect. She was helping people be safe and get out of the way and they shot at her.
'I was told she was helping people and saving them... I know she would have wanted a make everyone else safe. She would have been the first one to go down to confront somebody.'
Dawn described Acker as 'one of the strangest, quirkiest individuals I’ve ever known' and added that her partner 'loved her family'.
Dawn told the Statesman: 'I know that there’s different gender things, but I know that I can say she didn’t care what her family thought of that at all. She knew that she loved them and that they loved her.'
A grieving Dawn recalled how Acker also 'talked like a '90s mom' because she used words like 'goober' and 'adored' her cats Sebastian and Peridot' more than anything in the world,' according to the Statesman.
She 'had the palate of a 10-year-old,' Dawn noted, adding that her lover - who she also described as a 'proud nerd' - enjoyed french fries and pizza more than anything else.
Kevin Goncalves, who was stationed in Italy with Acker, told the Statesman that Acker was introverted, a lover of video games, 'an excellent runner' and a caring person.
She 'always stood up for the right thing, even if it brought trouble. That was always something I admired about Jo,' he added.
The shooting left two people dead at the scene and t five others, including Bergquist and a police officer, injured
Acker's friend Dominique Cairistiona said of her death: 'I have very confusing emotions right now. On one hand I’m upset that she was selfless and put herself in danger - but on the other hand I would expect nothing less of her.
'That’s exactly her character, to do whatever she could to help as many people as she could.'
Acker's high-school friend Shiloh Ren agreed and said Acker was a 'radiantly sweet person,' adding that she will be remembered as the first one to try and cheer someone up.
Ren told the Idaho Press: 'She had this presence about her that just made you feel safe and respected. She is going to be missed by many but forgotten by none.'
Meanwhile, when the officers arrived they spotted someone who matched the description of the suspect and at least one officer exchanged gunfire with him in the mall parking lot. A bullet injured a 69-year-old woman sitting in her car.
Bergquist was then arrested and taken to the hospital along with the officer he shot at.
The injured cop was treated and released from the hospital on Monday evening. As of that time Bergquist was in critical condition but he would not survive. The coroner said that he died late Tuesday morning.
Investigators believe Bergquist acted alone and Lee confirmed at the conference that there is no ongoing danger to the public.
The BPD said the suspect had more than one gun and a total of 18 shell casings were found inside the mall.
The investigation into Bergquist's motive is still ongoing and a search warrant was issued at a home on Fry Street - less than two miles away from the Boise Towne Square - according to CBS.
When officers arrived at the mall they spotted someone who matched the description of the suspect and at least one officer exchanged gunfire with him in the mall parking lot. A bullet injured a 69-year-old woman sitting in her car
The Boise Police Department (BPD) said the suspect had more than one gun and a total of 18 shell casings were found inside the mall
'There is...a multi-state effort underway to learn more about the suspect. We have been coordinating with our local, state and federal partners to investigate rumors and reports from social media and there is no evidence of additional planned attacks or ongoing threats to the public,' Lee said.
After the shooter shot and killed Acker he then fired several rounds inside the mall, hitting the glass escalator and a second unidentified victim who later died from his injuries at the hospital.
Bergquist continued firing throughout the mall. According to CBS he shot into the floor and injured two females. A male victim was also taken to a hospital and treated for injuries after he fell while rushing out of the building.
Video recorded by shoppers who were at the mall at the time of the shooting showed people running from the exit doors at shots were being fired. People were also heard screaming in the background.
Shopper Cheri Gypin said she thought something had fallen from the ceiling when she heard large bangs. Then she and a friend saw about 60 people, including families pushing strollers, come running at them - with some shouting there was an active shooter at the mall on Monday afternoon.
North and Southbound lanes on Milwaukee Street between Emerald and Franklin roads were closed as police cars swarmed to the scene
Bergquist fired multiple rounds throughout the mall. He even shot into the floor and injured two females. A male victim was also taken to a hospital and treated for injuries after he fell while rushing out of the building
Officers are still investigating the motive behind the shooting
Gypin said: 'My friend was trying to process it. I just looked at her and said: "We've got to run."
'So we just ran and kept running until we got to the outer perimeter of the parking lot.'
North and Southbound lanes on Milwaukee Street between Emerald and Franklin roads were closed as police cars swarmed to the scene.
The Boise Towne Square is the largest shopping mall in the city with more than 153 stores.'We are heart broken and are working closely with the Boise Police Department as they investigate the circumstances that led to this terrible tragedy,' the mall wrote in a Facebook post.
'In observance and respect for our community our shopping center will be closed tomorrow. This is a developing investigation,' it added.