She was 83 years old.

Making a Murder's Steven Avery's mother has passed away after a battle with dementia. Only a day before Steven's birthday, his mother Dolores died at the age of 83 on Thursday. Steven's attorney Kathleen Zellner revealed yesterday that Dolores had died on Twitter, saying: "Fate dealt another cruel blow to Steven Avery today, right before his birthday tomorrow; his mother Dolores Avery passed away at 6.50am." "He needs your support now more than ever." https://twitter.com/ZellnerLaw/status/1413198887255425029 Steven is currently serving his life sentence in Waupun Correctional Institution in Wisconsin for the murder of Teresa Halbach in 2005. Claiming his innocence since the murder occurred, the case was the focus of Netflix documentary Making a Murder which looked into whether he was innocent or not. Dolores took part in the series, and like her son, consistently proclaimed he was innocent. Reportedly passing away after a battle with dementia, TMZ say that Dolores had been in a hospice for three weeks prior her death. [caption id="attachment_274962" align="alignnone" width="620"] Steven Avery was convicted in 2007[/caption] Steven made a statement to TMZ, which read: "Losing my parents before I got out has always been my worst nightmare. Now it has happened.

"I worry my Dad will not live to see me as a free man.

"Today I lost the person I most wanted to take care of and give a better life when I am freed. I cannot put in words the pain of losing my mom."

Avery rose to fame back in 2015 when the Netflix documentary detailed the realities of the US criminal justice system, suggesting that Avery and nephew Brendan Dassey were framed for the murder.