DALLAS (CBSDFW.COM) – On August 18, 2016, Mary Jo Jennings spent the day shopping with her mother. She says Leah Corken was in fine form.

Corken posed for a picture wearing a big smile.

“She’s sassy. She’s got her hand on her hip.” says Jennings describing the last photo she took of her mom.

Leah Corken (courtesy: Mary Jo Jennings)

The next morning, Jennings says they spoke over the phone as they always did. But by that evening Jennings arrived at The Tradition-Prestonwood, an independent living facility, to find the 83-year-old dead, lying face-down on the ground.

“There was just something really uneasy about the way I found her. Her body was positioned in a very straight line with her face on the carpet. Something just felt unusual.” Jennings said.

Another red flag for Jennings: her mother wasn’t wearing her beloved wedding ring.

She says she expressed her concerns to staff at The Tradition-Prestonwood and they tried to reassure her.

“I was told ‘that’s how people drop dead.’ I was consoled, and assured that she died naturally,” she says.

Suspected serial killer Billy Chemirmir is facing charges for the murders of 12 elderly victims.

Billy Kipkorir Chemirmir (credit: Dallas County Sheriff’s Department)

Investigators say he would strangle or suffocate his victims to steal their valuables. He has been formally charged in the murders of two people at the North Dallas independent living facility.

Lawsuits filed on Tuesday claim six other residents at that location–including Jennings’ mom–also died at the hands of Chemirmir.

“We now know with Google location tracking data that [Chemirmir] was in our clients’ loved ones’ residences at the time they were killed,” says attorney Dave Wishnew.

Those lawsuits claim the independent living facility failed to live up to its safety and security promises and that its “lack of internal surveillance cameras and security measures” gave Chemirmir “unfettered” access to his victims.

“Tradition should have done everything that they had promised they would do: Provide all of the exceptional level of security that they marketed to the elderly and the families who brought their loved ones to their facilities,” Wishnew says.

They also allege that The Tradition knew that someone was stealing “substantial amounts of jewelry from residents who had suddenly and unexpectedly died in their own apartments– and that burglaries occurred before or at the time of death.”

The residents died within 3 months of one another. Families say they noticed and reported valuables missing–including a safe, and $28,000 worth of jewelry.

“They knew Chemirmir was on the premises and they didn’t disclose it and in some instances lied about it,” Wishnew claims.

The Tradition provided the following statement to CBS 11 News:

“The deaths by an alleged serial killer in people’s homes and at multiple senior living communities in the DFW Metroplex is a true tragedy.
The Tradition-Prestonwood regards all our residents as family.
The Tradition-Prestonwood relied on the investigations of the Dallas police, its detectives, and other reputable, established governmental entities, including the Dallas County Medical Examiner, the Collin County Medical Examiner, and more. Any death was investigated by Dallas police and the Dallas County Medical Examiner and ruled as attributed to natural causes. Additionally, there were two autopsies which also confirmed death by natural causes.
Those rulings stood for more than 27 months.
The Tradition-Prestonwood has cooperated with all the authorities and will continue to do so. The allegations against Mr. Perlman that he withheld information are absolutely false.”

Chemirmir has not been charged in these additional six deaths, though Jennings says it is only a matter of time.

“I am confident that that will happen sooner than later,” she says.

Jennings told CBS 11 she hopes this lawsuit will help bring about change beyond the walls of The Tradition.

“I want the owner of The Tradition to take responsibility for lack of security. I want changes to be made in independent living homes where there is more security. This was preying on the elderly.”