PICO RIVERA — Detectives have arrested a man on suspicion of murder in connection with a body found buried in a shallow grave in a Pico Rivera backyard last week, authorities confirmed Tuesday.

Robert Charles Redd, 51, was being held in lieu of $1 million bail at the sheriff’s Pico Rivera Station, according to sheriff’s booking records.

He appeared in Whittier Superior Court Tuesday, where his arraignment was postponed until Aug. 16.

Redd spoke only three words during the proceeding. When asked by Judge Mark Nelson whether he waived his right to a speedy trial, he responded, “Yes I do.”

Redd was arrested on suspicion of murder Friday afternoon, according to sheriff’s officials and records, though authorities did not disclose the arrest until Tuesday.

Additionally, Redd was accused of the special allegation of personally using a firearm in the killing, according to a felony complaint filed against him in Whittier Superior Court.

The complaint alleged the murder was done, “with malice aforethought.”

Redd was being represented in court by Sean McDonald of the Los Angeles County Public Defender’s Office. The case is being prosecuted by Deputy District Attorney John Pomeroy.

Redd was jailed on a lesser felony and held in lieu of $20,000 bail early Thursday morning, just hours after the body was discovered, before detectives decided to book him on suspicion of murder the following day.

Friends and family members looking for a 19-year-old man they had not seen in several days went to a house they knew he frequented in the 8500 block of Pico Vista Road about 6:30 p.m. July 20 when they discovered human remains buried in a shallow grave in the backyard and called authorities, sheriff’s officials said in a written statement.

A coroner’s special recovery team excavated the site and removed the body — later identified as 19-year-old Joseph Rubalcaba of Pico Rivera — Los Angeles County Department of Coroner Assistant Chief of Operations Ed Winter said.

An autopsy determined that Rubalcaba died from a single gunshot wound to the head, officials said, and the death was ruled a homicide.

According to the felony complaint, the killing took place “on or about July 18.”

Redd appeared in court Tuesday with salt-and-pepper hair and a mustache, his hands shackled at the waist of his orange jail jumpsuit. His face remained emotionless during the brief hearing.

A motive in the killing has not been released.

A memorial of candles, flowers and handwritten notes stood in front of the home Tuesday. A pickup truck neighbors said belonged to Redd remained in the driveway.

Neighbors said Redd was known in the neighborhood as “Bob” and had lived in the home for less than a year. Several of them said a large number of different people constantly came and went from the home.

Redd was often seen doing yardwork in his front yard.

Many neighbors also said they would greet Redd in passing, but did not know him personally.

A search of Los Angeles County court records show he has never before been convicted of a violent crime.

If convicted as charged, Redd faces 25 years to life in prison.