LAS VEGAS (KLAS) — The mother of a 4-year-old Las Vegas boy found deceased in a freezer has filed a wrongful death lawsuit against the man accused of killing her son and allegedly holding her and her daughter against their will for months.

Mason Dominguez’s body was discovered last month inside 35-year-old Brandon Toseland’s garage concealed in a trash bag in a freezer. Detectives believe Mason had been there for at least 10 weeks and that a large hole in the backyard may be a potential grave, the 8 News Now I-Team first reported.

Mason’s 28-year-old mother said she and her two children, Mason and a 7-year-old girl, moved into Toseland’s home in March 2021. The home is located on Saddle Brook Park Drive, near the intersection of Carey Avenue and Lamb Boulevard in the northeast valley.

The mother met Toseland through her husband, who died in January 2021. The mother said she was locked in a room and separated from her children for months.

“Between March and July of 2021, Toseland began systematically alienating [the mother] from her family and friends, in small incremental, but increasing acts of domination and control,” the lawsuit said.

Toseland had installed a video camera system throughout the home, the lawsuit claims.

In July of last year, Toseland forbid the mother from seeing her family, the lawsuit said.

Toseland kept the mother isolated from her children by locking her in a separate room, the lawsuit said. Toseland also is accused of taking control of her phone and social media accounts. When police arrested Toseland last month, the mother’s phone was in his possession, police told the 8 News Now I-Team.

Police were alerted to the home after being contacted by Clark County School District Police when the 7-year-old girl brought a note to her teacher that her mother was being held against her will and did not know what happened to her younger child.

Mason Dominguez (KLAS)

Toseland’s girlfriend, the boy’s mother, told Metro police she had not seen Mason since Dec. 11, and feared he might be dead.

Court documents said Toseland told Mason’s mother that Mason was ill in early December. He said he found him unconscious and that she could not see the boy’s body.

“In early December 2021, [the mother] came home from work and Mason appeared ill. [The mother] wanted to take him to the doctor, but Toseland told her he would help him and take care of him,” the lawsuit said.

Toseland reportedly told his girlfriend that he had taken Mason into a bedroom and locked him inside with him for several days. He then told his girlfriend that Mason was deceased, documents said.

According to the wrongful death lawsuit, Toseland told the mother that Mason’s death was accidental. His cause and manner of death remained pending Monday.

“[The mother] noticed that her son Mason often had bruises and Toseland told her that the dog knocked him over, or that he fell, frequently explaining his injuries as accidental and referring to Mason as clumsy,” the lawsuit said.

Brandon Toseland (LVMPD/KLAS)

Starting in December, Mason’s mother hatched a plan to write notes to send through her daughter, Stubbs said.

“Over a period of weeks, [the mother] found some sticky notes in the car and for the few seconds that she would be alone in the car while Toseland walked [her daughter] into her school, she began scribbling SOS messages and trying to devise a way to get help without both of them being killed,” the lawsuit said.

On Feb. 20 and Feb. 21, Toseland allowed the mother and daughter to sleep together. The mother then told her daughter she was going to give her “important notes” to give to her teacher.

On Tuesday, Feb. 22, the mother hid the notes in her daughter’s sock.

When Metro officers arrested Toseland later that day, initially on suspicion of kidnapping, they noticed a handcuff attached to the car where Mason’s mother was sitting.

Toseland, 35, faces two counts of kidnapping and one charge of open murder in the death of 4-year-old Mason Dominguez. Toseland had previously faced domestic violence charges and was ordered to attend counseling in an unrelated case, records obtained by the I-Team said.

Family home where Mason was discovered (KLAS)

The lawsuit claims several causes of action, including Mason’s wrongful death and the false imprisonment of the mother and her daughter.

Toseland had previously faced domestic violence charges and was ordered to attend counseling, records obtained by the 8 News Now I-Team said.

Toseland is due in court in April on kidnapping and murder charges.