A Texas woman and her boyfriend have been charged with capital murder after authorities say they killed her mother and stepfather and disposed of their bodies in a ravine.

Cassandra Lange, 29, and Joby Williams, 30, are accused in the deaths of 54-year-old Cherry Rehbein and 58-year-old Stephen Rehbein, according to the Medina County Sheriff’s Office. Both suspects are being held on $1 million surety bonds.

Investigators allege that the killings took place on Monday at the couple’s home on County Road 265 in Mico, a community west of San Antonio.

According to Medina County Sheriff Randy Brown, Lange and Williams are believed to have first killed Cherry Rehbein inside the home. When Stephen Rehbein returned from work later that day, he was also killed.

Authorities say Lange is Cherry Rehbein’s biological daughter and Stephen Rehbein’s stepdaughter.

The case came to light two days later, when a co-worker reported that Stephen Rehbein had not shown up for work. Deputies conducted a welfare check at the home but were unable to make contact with anyone inside.

While at the property, deputies observed signs of possible foul play, including what they described as bloody items in a trash can outside the residence. Investigators then obtained search warrants and began tracking vehicles associated with the victims.

One of those vehicles was later located traveling in the Corpus Christi area, roughly 150 miles southeast of Mico. Law enforcement stopped the vehicle and found Lange and Williams inside, along with two children.

Authorities said the children included Lange’s 6-year-old daughter and a 1-month-old baby. Williams is the biological father of the infant, according to local reports.

The 6-year-old was released to her father, while the infant was placed in the care of state child protective services.

Following their detention, both suspects were interviewed by investigators. According to the sheriff’s office, Lange confessed that she and Williams had killed her mother and stepfather and disposed of their bodies in a nearby ravine.

Deputies then began searching the Medina Lake area, where they believed the remains had been left. Officials said the search was difficult due to terrain and nighttime conditions.

During the search, deputies located two large black garbage bags concealed in a deep ravine. The remains recovered from the scene were sent for autopsy to confirm their identities and determine the causes of death.

Authorities have not released additional details about a possible motive.

The investigation remains ongoing as officials continue to gather evidence in the case.