A suspect in the murder of 37-year-old Mark Salinas was arrested on Thursday at approximately 10 p.m. 

According to Duval County Sheriff Romeo Ramirez, authorities arrested Mary Ellis Salinas in connection with the murder of her twin brother.

In September, Mark Salinas was found with a gunshot wound to the back of his head at a ranch on County Road 321 off Farm-to-Market 3196, just west of San Diego.

According to a member of Mark's family, Mary confessed to the murder of her brother. 

Mark Salinas had an open investigation of sexual assault of a child with the Alice Police Department at the time of his death.

No murder weapon has been found by investigators.

According to police officials, Mary Salinas initially told investigators she went to check on the property when she found Salinas face down on the ground.

The Texas Rangers and Jim Wells County Sheriff's Office also assisted in the investigation.

She was booked into the Duval County jail.

Salinas was charged with murder and was given a million dollar bond.