Officers spent much of the day Wednesday and Thursday at a home in the 200 block of Curnow Road and 5000 block of Grass Creek Drive.

A neighbor told 23ABC that recently, they saw the man who was renting the home, identified as 45-year-old Frank Valles, using a small tractor in the back yard.

"He was out there messing around for a couple hours. You could say a full day," said neighbor Martin Guzman.

"We thought he was going to go plant something but after he was digging for a while we thought he's not going to plant anything, probably going to bury somebody," said neighbor Eliseo Ibarra.

"It was crazy. Kind of suspicious. He was putting a guard up between the fence like he wanted privacy," said Guzman.

BPD says the investigation started Tuesday when they received a tip about remains buried at home on Grass Creek Drive.

Investigators discovered human remains buried in the back yard and while they were there, Valles arrived at the home.

Detectives took him to BPD for questioning.

They discovered Valles lived at the home on Grass Creek Drive in the past.

They questioned another unidentified person.

Information from both interviews led them to Valles' current home on Curnow road, where they discovered more human remains buried in the back yard.

Police say the remains are partially decomposed and are those of at least one victim.

Detectives say Valles knew the victim but are not disclosing the relationship.

Valles has been arrested for first degree murder.

He is scheduled to be arraigned in court Friday afternoon.

Police have no other suspects.