(CNN) — Two brothers are now under arrest in connection with this week’s kidnapping and killings of four California family members — with one brother held on suspicion of murder and the other accused of being an accessory, authorities said Friday.

Jesus Manuel Salgado — a former worker at the victims’ family business — was formally arrested late Thursday on four counts of murder and four counts of kidnapping in the case, Merced County sheriff’s spokesperson Alexandra Britton said.

Salgado’s brother, Alberto Salgado, also was arrested in the case Thursday night on preliminary charges of criminal conspiracy, accessory, and destroying evidence in connection with the case, Britton told CNN Friday.

Authorities say the four slain family members — 8-month-old Aroohi Dheri, her parents Jasleen Kaur and Jasdeep Singh, and the child’s uncle, Amandeep Singh — were kidnapped from the family’s trucking business in the central California city of Merced on Monday, and parts of the kidnapping were captured on surveillance video.

On Wednesday, the bodies of the four were recovered from an orchard in Merced County after a farmworker alerted authorities to the remains.

As Merced County Sheriff Vern Warnke announced the family’s bodies had been found Wednesday evening, he said “there’s a special place in hell” for the perpetrator.

“The circumstances around this, when we are able to release everything, should anger the hell out of you,” Warnke said.

Jesus Salgado was detained in the case on Tuesday after his family told law enforcement he admitted to being involved in the kidnappings, authorities said.

The sheriff’s office did not immediately release details about the accusations against Alberto Salgado, other than the charges on which he was being held.

Jesus Salgado, 48, used to work for the victims’ business, Britton told CNN Thursday. She did not provide details, including the position he’d held.

CNN was not immediately able to identify attorneys for the Salgado brothers, and calls to family members have gone unanswered.

As the investigation continues into the motive behind the killings, here’s what we know about the case.

How was the family kidnapped?

Surveillance footage released by authorities shows how all four family members were taken against their will from their workplace in Merced on Monday morning.

At 8:30 a.m Monday, the video shows Jasdeep Singh arriving at the business’ parking lot, followed by Amandeep Singh arriving nine minutes later.

Shortly before 9 a.m., Jasdeep encounters a man outside the business. The man carries a white trash bag and pulls out what appears to be a firearm, the video shows.

At around 9:11 a.m., the video shows that Jasdeep and Amandeep have their hands tied behind their backs and get into a truck, which leaves shortly after.

Minutes later, the vehicle returns to the parking lot and the man enters the business. The man exits with a gun in hand, leading away Jasleen Kaur as she holds 8-month-old Aroohi.

Investigators first learned the family was missing after a family vehicle was found abandoned and on fire Monday morning, authorities said.

Also Monday, a farmer found two of the victims’ cell phones on a road, authorities said. At one point, the farmer answered one of the phones and spoke with a relative of the victims.

What do we know about the suspects?

Officials have said they believe Jesus Salgado — the person they took into custody Tuesday — was the main suspect in the case.

But even before the arrest of his brother was announced Friday, the sheriff said others beside the main suspect could have been involved.

“I fully believe that we will uncover and find out that there was more than just him involved,” Warnke said Wednesday.

Authorities have yet to say how, precisely, Albert Salgado is connected to the case.

As for Jesus Salgado: He served a lengthy prison sentence for a similar crime back in 2007. He was sentenced to 11 years behind bars for charges including first-degree robbery with use of a firearm and attempted false imprisonment, according to the California Department of Corrections and Rehabilitation.

Also in 2007, he was sentenced for possession of a controlled substance, the corrections department said. He was released on parole in 2015 after finishing his sentence and completed parole in 2018, according to the department.

Before police took Jesus Salgado in on Tuesday — initially as a person of interest — Jesus Salgado attempted suicide and received medical treatment that caused him to be sedated because he was acting violently while conscious, Warnke said.

Jesus Salgado was talking to investigators, Warnke said, but didn’t elaborate on what information he may have shared.

“We got information from the suspect, we are going to keep that close to our chest at this point,” Warnke said.

Both Salgado brothers have been booked at the Merced County Jail, the sheriff’s office said.

How has the investigation unfolded?

Among the questions that remain unanswered is the motive behind the family’s killing.

“We have a whole family wiped out, and for what? We don’t know yet,” Warnke said Wednesday after the bodies were recovered.

Authorities have also not disclosed how the family died, but did reveal it appears they were killed where they were found, and the killings happened before the sheriff’s department was notified Monday that the family was missing.

A day after the family was kidnapped, authorities learned an ATM card belonging to one of the victims was used at a bank in Atwater, California, the sheriff’s office said in a statement. Atwater is about 9 miles northwest of Merced.

Who used that card wasn’t immediately clear, according to Britton.

“Investigators obtained the surveillance photo of a subject making a bank transaction where the person is similar in appearance to the surveillance photo from the original kidnapping scene,” the sheriff’s office said earlier this week.

Join our Newsletter for the latest news right to your inbox