PHOENIX (3TV/CBS 5) - Sources close to the missing Idaho children investigation told CBS News that Alex Cox, Lori Vallow's brother, may be linked to Tammy Daybell's death. However, he died before he could be questioned.
Lori is behind bars in Rexburg, Idaho facing several charges related to her two missing kids, JJ and Tylee, who were last seen in September.
Tammy, a beloved school librarian in Rexburg, died in her sleep in October. Two weeks later, Lori married Tammy's widower, Chad Daybell.
After police started looking into the whereabouts of the kids, the death of Lori's previous husband, and other attempted murders, Tammy's body was exhumed.
[TIMELINE: Missing Idaho Kids Investigation]
The day after her body was exhumed, Alex died. His death is also under investigation. Records show that Alex has a long history of causing trouble. In 2007, he threatened to kill Joseph Ryan, Lori's third husband, and Tylee's biological father. Alex assaulted him with a stun gun and was convicted of aggravated assault. Joseph died in 2018 of an apparent heart attack.
In July 2019, Alex shot and killed Charles Vallow, Lori's fourth husband. Charles had filed for divorce earlier that year and wanted custody of JJ. The shooting happened when Charles arrived at their Chandler home to take JJ to school. The police report states that there was an altercation of some sort, and Tylee went to her room to get a bat, which Charles took from her and then hit Alex.
Newly released police records show a man who was killed last summer when picking up his son from his estranged wife in Chandler was confronted by his baseball bat-wielding stepdaughter.
"I turned around, and he hit me in the back of the head with the bat, so I went to my room and got my gun," Alex said on police body camera footage. In the body camera footage, the home was nearly empty. Alex told officers he was only visiting. Shortly after Charles was killed, Lori moved to Rexburg with the kids, and Alex followed.
On September 8th, Lori, Alex, JJ, and Tylee took a trip to Yellowstone National Park. In photos recently released by the FBI, Tylee and JJ are seen smiling together with Alex in the background. Tylee has not been seen since that day.
Brandon Boudreaux, the ex-husband of Lori's niece Melani, claims that Alex shot at him in October while in Arizona. Police believe the vehicle seen leaving the scene of the crime that day was registered to Charles; it was later found in Idaho.
Tammy also wrote on Facebook before her death, saying that someone tried to shoot her in her driveway. Alex died in his Gilbert home in December. Autopsy results have not been released for Alex or Tammy's deaths.
Gilbert and Chandler Police Departments confirm detectives will be heading up to Salt Lake City this week to meet with other agencies involved in this case. Lori has not posted bond.