Mandoyan, 47, says the sudden notoriety has ruined his life and taken a toll on his family.
He believes he is a political pawn between newly elected Sheriff Alex Villanueva and the powerful Los Angeles County Board of Supervisors.
The issue? Allegations of stalking, lying and abuse leveled in 2015 by Mandoyan's ex-girlfriend, who was also a deputy. Then-Sheriff Jim McDonnell fired Mandoyan and the County's Civil Service Commission upheld the termination.
"It's a lot of hurt, a lot of hurt - a lot of crying," says Mandoyan. "And I've done everything I can to shield my kids from it. I know it's affected my family, it hurts."
Sheriff Villanueva rehired Mandoyan as one of his first official acts, a move the Board of Supervisors say was illegal.
Video that surfaced this week appears to show Mandoyan trying to break into the ex-girlfriend's El Segundo apartment years ago. Mandoyan says they shared the apartment and that he stayed there four or five days a week.
She had locked him out on the patio after a fight.
"I had my backpack, my duty weapon, my badge, my gun, my keys were all inside," says Mandoyan. "I had no way means to go anywhere to cool off."
"At this point, like I'd done before, I grabbed the plastic broomstick and I'd tap on the glass to get her attention to let me in," he says.
Mandoyan says she ignored the broomstick tapping, so he grabbed a piece of gym equipment on the patio.
"I used the cable pulley," he says. "It was not a pry bar, it was not a crow bar as it was made out to be."
"I wanted her to let me back in," says Mandoyan. "And she ultimately did a few minutes later, which isn't on the tape."
Mandoyan showed ABC7 text messages he says were from later that same night.
"I love u," he wrote in the text.
"I love you!" was the reply.
THEN.... THE REAL TROUBLE BEGAN
The real trouble came later after their break-up. Mandoyan says he began to date a woman who used to be friends with his ex-girlfriend. The two women -- both deputies -- had had a falling out years earlier. Mandoyan's relationship with the second female deputy also unraveled months later when Mandoyan says he learned his new girlfriend was sending nasty text messages to his ex-girlfriend.
"Pretty much antagonizing her... and calling her fat, calling her Shamu," Mandoyan says.
Mandoyan says the messages he saw were sent from an unknown number or a burner phone. He says the first ex-girlfriend thought the messages were coming from him.
In early June of 2015, Mandoyan says he got a call at work from the first ex-girlfriend - the same one who'd recorded him on the patio six months earlier.
"You're a stupid mother-f-----, say goodbye to your f---- job," Mandoyan says she screamed. "When I'm done with you... you'll need a psych eval to get your job back."
"I'm gonna call your watch commander and I'm gonna tell him you broke into my house and whatever else I want to say," Mandoyan says she told him.
Mandoyan says she'd called him drunk on many occasions, but he was alarmed because this was the first time she'd threatened to level false allegations against him.
Mandoyan showed ABC7 a memo he says he wrote that same day to his Lieutenant to document the phone call.
Weeks later, Mandoyan says the first ex-girlfriend "apologized for calling me and making the threats," and even invited him over to visit as a friend.
He thought everything was fine, but says he later learned the two ex-girlfriends had rekindled their friendship.
"Now, I have two angry, upset female deputies and this is where the whole nightmare began," he says.
A KNOCK ON THE DOOR...
Mandoyan says his world collapsed on the night of July 10th when he got a knock on the door at home. He was being relieved of duty by the Los Angeles County Sheriff's Department.
"They said sorry -- we have to relieve you of duty, we need your badge and gun," he says. "I had no idea what was going on. I'd never been in trouble in my career, I'd never been disciplined and they couldn't tell me why!"
Mandoyan says he didn't think it was related to his first ex-girlfriend because of her recent apology and their visit.
Then things got even stranger. A few days after he was relieved of duty, there was another knock on the door. Mandoyan says it was his second ex-girlfriend with two El Segundo police officers. They were serving a temporary restraining order on behalf of the first ex-girlfriend.
"It was two scorned ex-girlfriends that wanted to settle a score with me, and I became the victim of it, at my expense," Mandoyan says.
Eyewitness News spoke briefly with the first ex-girlfriend last week. She said the entire episode gave her anxiety. She told our producer she wanted nothing to do with the current controversy.
After Eyewitness News knocked on her door again this week, we got a phone call from law enforcement saying she'd asked to have us arrested if we returned.
MANDOYAN: "I NEVER LAID A FINGER ON THIS GAL"
As for the allegations of abuse? Mandoyan maintains they are flat-out lies.
"I've never laid a finger on this gal - ever," he says. "I've handled numerous domestic violence cases, I've helped numerous domestic violence victims. To me, that hurt more than anything else."
Los Angeles County Sheriff's Deputy Lisa Richardson tells Eyewitness News she worked with both Mandoyan and the first ex-girlfriend and tried to mediate their disputes.
"She was concerned about breaking up with him," Richardson says. "She said - I don't want to break his heart."
Richardson says her law enforcement training kicked in and she pressed the female deputy... was she afraid of him... had she been abused?
"I specifically asked her - have you been hit... have you been pushed," Richardson says. "She made it crystal clear to me - no, I have not been hit, I have not been pushed. I would be the one who would kick his ass."
Mandoyan's attorney, Greg Smith, says the interview Deputy Richardson recorded for investigators was somehow lost and never presented at Mandoyan's civil service hearing.
The temporary restraining order against Mandoyan was dissolved two weeks after it was filed when Mandoyan and the ex-girlfriend both signed a "dispute resolution agreement."
Five weeks later, the DA's declined to file charges criminal charges against Mandoyan.
But Mandoyan remained relieved of duty and was ultimately fired by Sheriff McDonnell in 2016.
As for his two ex-girlfriends? Mandoyan believes they wanted revenge, but never thought it would go this far.
"I don't think neither one of them knew how far this was going to go and how much damage this was going to cause," Mandoyan says. "Had they known, I don't think neither one of them would've done it."
Got a tip? Email ABC7 Investigative Producer Lisa.Bartley@abc.com