The 18-year-old suspect in the shooting death of an Alabama sheriff is facing new capital murder charges that could make the teenager eligible for the death penalty.

»PREVIOUS COVERAGE: An Alabama sheriff was slain over the weekend — here's what we know

William Chase Johnson had originally been charged with murder in the Nov. 23 slaying of Lowndes County Sheriff John Williams, a charge that carries only a maximum sentence of life in prison.

District Attorney Charlotte Tesmer announced the upgraded charges Tuesday after a judge signed the capital murder warrant.

Johnson, who is the son of a sheriff’s deputy in a neighboring county, is accused of fatally shooting Williams last month at a QV gas station in Hayneville, Alabama, about 20 miles southwest of Montgomery.

The shooting happened on a Saturday night.

Police said the sheriff was responding to a report of loud music at the store, according to multiple reports. Police say Williams approached a truck at the gas station and asked a man sitting inside to turn down the volume on his stereo.

An eyewitness described seeing the sheriff exchanging words with a man at one of the gas pumps about 8:15 p.m. Moments later, a single shot rang out, and Williams was wounded in the head.

A photo provided by the Elmore County Ala. Sheriff's Office shows William Chase Johnson, a suspect in the fatal shooting of Lowndes County Sheriff John Williams.

Credit: Elmore County Ala. Sheriff's Office

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Credit: Elmore County Ala. Sheriff's Office

After a four-hour manhunt, police said Johnson returned to the crime scene and surrendered. He had a handgun when he was arrested without incident and taken to the Elmore County Jail. He made his first appearance in court Nov. 25, where he was formally charged in Williams’ death.

Deputies, police  and state law enforcement work the scene of a QV gas station in Hayneville, Ala., where Lowndes County Sheriff John Williams was shot and killed Nov. 23.

Credit: Kirsten Fiscus

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Credit: Kirsten Fiscus

More than 2,000 people attended a funeral service for the beloved sheriff known as “Big John” on Monday at Garrett Coliseum in Montgomery. Williams was remembered as a "true peacemaker."

“He was a true peacemaker, a true servant of God,” Montgomery County Sheriff Derrick Cunningham told the crowd. He was one of three Alabama sheriffs who spoke during the service.

The day after Williams’ death, law enforcement agencies in Alabama and beyond posted messages of condolences on social media.

Lowndes County Sheriff John Williams was fatally shot in the line of duty on Nov. 23.

Credit: Mickey Welsh

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Credit: Mickey Welsh

Alabama Gov. Kay Ivey also paid tribute to him online, writing that in the sheriff’s years of service in the U.S. Marine Corps and “his many years working in law enforcement, he dedicated his life to keeping other people safe.”

According to Alabama law, killing a law enforcement officer on duty, regardless of whether the defendant knew the victim was a police officer at the time, is a capital offense.