Colorado authorities have locked up the mother of a man who they say was killed over the family ranch worth millions of dollars.

Deborah Rudibaugh, 68, who lived on the Gunnison County ranch, was arrested Friday and charged with murder in the death of her 29-year-old son Jacob Millison in 2015.

Her arrest is the second in the case. On Wednesday, her 33-year-old daughter Stephanie Jackson, 33, was charged with murder. Jackson is also Millison’s sister.

Rudibaugh’s role in the murder was unclear, the Grand Junction Daily Sentinel reported.

According to the paper, Gunnison County Undersheriff Mark Mykol said “she is a suspect” but declined to elaborate.

Mykol said in a press release that Rudibaugh was arrested without incident in another county and transported to the same county jail where her daughter is being held.

WOMAN ACCUSED OF KILLING BROTHER OVER HUGE COLORADO RANCH WORTH MILLIONS

Rudibaugh was being held without bail. Jackson was being held in lieu of $500,000 bond.

Rudibaugh has also been charged with abuse of a corpse, concealing a death, tampering with a deceased report and filing a false report, Mykol said.

The motive for Millison’s murder was his family’s sprawling 700-acre ranch property that reportedly worth millions of dollars.

Mykol said after Jackson’s arrest that the murder was “definitely ranch-related.”

The ranch was where authorities found Millison’s body last year after receiving a tip.

After the body was found CBS4 Denver reported trying to interview Rudibaugh. She told the station that she wouldn’t comment because of the “active investigation.”

The station reported at the time that Rudibaugh reported her son missing in August 2015.

The station reported that friends of Millison said he had not been seen or heard from for months before then.

They had reported him missing in May 2015.

Investigators said they know how Millison was killed but aren't releasing that information.