A few years earlier in 2016, Crystal Straus, the murder victim's sister, had heard about the evidence and wrote a letter to Tiedjen in prison "offering her forgiveness" according to Local12.
Brian was Crystal's half-brother and Tiedjen's stepbrother.
He had lived with Tiedjen's family since he was 15 and they were roommates.
Tiedjen, who responded to Crystal's letter to share the "stuff" that he claims will prove "I didn't do it", is now under house arrest until the new trial begins on August 31.
The pair tied the knot in the backyard of his home with Crystal wearing a simple blush pink gown, Tiedjen in navy pants and a white shirt.
A clip of the ceremony was uploaded on Instagram and a lawyer appeared to preside over the nuptials.
"I love him, obviously. If I didn't love him I would not be sitting here with him," she said.
Tiedjen told News5 Cleveland that he loves Crystal with "all his heart".
He proposed to Crystal on the phone on New Year's Eve last year as the pair feared he wouldn't be released from jail.
It's reported that Crystal first wrote to John while she was making a trip to Lake Erie in 2016 but she didn't know why she had sent the letter.
But, the two stayed in contact, The Washington Post reports.
"We both had something in common, the loss of Brian. We started talking and it just sparked," she said.
Tiedjen was 25 when cops found Brian, then 18, dead in his bedroom.
He reportedly had a stab wound to his chest and a bullet hole between his eyes.
Detectives reportedly found Brian's blood on the barrel of the gun and bullets in Tiedjen's pockets.
Tiedjen reportedly told cops that he "couldn't remember" what had happened on the night of Brian's death.
Prosecutors claimed that his fingerprints were found on the gun as he was sentenced to life.
He said: "I had no powder burns, no gunshot residue, no blood, no cuts, no scrapes, nothing on me or my clothing."
Tiedjen remains under house arrest until his retrial begins on August 31.
