Authorities have arrested a man in the brutal murders of an Alabama mother, her pregnant teenage daughter and 12-year-old son, who were found bound in their home April 20.

Mobile County Sheriff Paul Burch said William Graham Oliver, 54, was charged with eight counts of capital murder, according to a report from local outlet WALA. He was booked into jail Tuesday.

Fox News Digital previously reported Mobile County Sheriff’s Office deputies responded to a home in Wilmer, Alabama, just after 2:30 a.m. April 20, where they found three bodies in separate rooms with their hands tied behind their backs.

The victims were identified as Lisa Gail Fields, 46, who was stabbed; Keziah Arionna Luker, 17, who was shot; and Thomas Cordelle Jr., 12, who had his throat cut and was nearly decapitated.

Burch described the scene as “brutal” and noted the home was “left in disarray.”

Luker’s 18-month-old child was found unharmed in the home.

Her unborn child, who was seven or eight months along, also died.

The unborn child’s father, who works offshore, triggered the discovery after he could not reach Luker when he saw her phone activated on Life 360, the sheriff said.

Another family member went to check on her and found the deceased family.

Burch said Oliver knew the family “for quite some time” and was inside the home “looking for something” the night before the bodies were found, according to the report.

“Very very tight timeline,” Burch told reporters. “Very solid circumstantial evidence at this point, and we feel confident that we have the right man.”

Burch said investigators have pinpointed what Oliver was allegedly looking for and his motive but did not release those details to the public, the outlet reported.

Shortly after the killings, investigators said they believed more than one person was involved in the killings because the victims had been subdued using zip ties and flex cuffs.

It is unclear if any additional suspects have been identified.

Jail records show Oliver was charged with first-degree theft of property in 2020, with other arrests dating back to 1990.

The sheriff’s office did not immediately respond to inquiries from Fox News Digital.