Louisiana Shooting

This photo provided by the Richmond County Sheriff’s Office shows Dakota Theriot on Sunday, Jan. 27, 2019. Authorities say a man suspected in two shootings that left five people dead in Louisiana has been arrested in Virginia. Ascension Parish Sheriff Bobby Webre and Livingston Parish Sheriff Jason Ard said in a statement that Theriot was arrested Sunday by the Richmond County Sheriff's Office. (Richmond County Sheriff’s Office via AP)

LIVINGSTON — The man accused of killing five people in suburban Baton Rouge last month was indicted on first-degree murder charges by a grand jury in Livingston Parish on Thursday.

The three-count indictment was the first set of formal charges filed against 21-year-old Dakota Theriot in the shooting rampage that authorities say ended the lives of his girlfriend, Summer Ernest, 20; her father, Billy Ernest, 43; her brother Tanner Ernest, 17; and the suspect's own parents. The indictment handed up Thursday covers the deaths of the three Ernests.

The first-degree murder charges open up the possibility that Theriot could face the death penalty, although prosecutors have not yet said whether they will seek to execute him.

Authorities have said Theriot was living with the Ernest family in a trailer outside Walker when, on the morning of Jan. 26, he shot each of the victims in the head. He then drove, authorities have said, to Ascension Parish and shot his own parents in the same fashion before fleeing to Virginia, where he was arrested the following day outside his grandmother's house.

According to the Livingston sheriff and the Ernests’ neighbors and relatives, Summer Ernest had recently started dating Theriot, who moved into her family’s home a few weeks before the killings, after his parents had kicked him out. 

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Law enforcement officials brought Theriot back to Louisiana on Friday to face murder charges in both parishes. Authorities have said he confessed but did not offer a motive.

The grand jury foreperson and Livingston Parish Assistant District Attorney Kurt Wall delivered the indictments Thursday to 21st Judicial District Judge Elizabeth Wolfe.

Wall said the grand jury heard from one witness.

The district attorney in Ascension Parish has not yet taken the case to a grand jury there. He has been booked on two counts of first-degree murder in that parish in the deaths of his parents, Elizabeth and Keith Theriot, both 50 years old.

Law enforcement reports show Theriot struggled with mental illness, possibly schizophrenia, and interacted with law enforcement in at least three parishes in the years leading up to the slayings.

Records obtained Thursday from the Livingston Parish Sheriff's Office show that deputies encountered Theriot in November, when he was reported as a suspicious person in Holden. The report says Theriot was knocking on an apparent stranger's door and saying three people were chasing him and he needed help. At the time, Theriot was listed in law enforcement records as homeless.

The deputy noted in a report that Theriot "seemed to not be in his right state of mind" and called an ambulance. The medical personnel decided to take him to Our Lady of the Lake Hospital in Walker for evaluation.

Nine months prior, Livingston Parish deputies had issued Theriot and his father, Keith, summonses for possession of a marijuana pipe after a traffic stop, records show.

What role Theriot's apparent mental illness or drug use played in the shootings remains unknown.

Livingston Parish District Attorney Scott Perrilloux has said reports of Theriot's mental illness are a reason he is taking a hard look at whether to seek the death penalty. Perrilloux said he also wants to consult with the family and consider the likelihood of a unanimous jury verdict in favor of lethal injection.

Although Theriot does not have an officially appointed attorney, Elliott Brown, a lawyer from the Louisiana Capital Assistance Center, has enrolled in a limited capacity and filed several motions in the case.

The motions ask 21st Judicial District Judge Robert Morrison III to protect various rights for Theriot, including that law enforcement officers preserve evidence and do not interview him again without an attorney present.

Morrison agreed to those requests, as well as one to grant Theriot a bond review hearing. But he wrote in a court order that it was premature to formally appoint a capital defender, since the state has not declared whether it will seek the death penalty.

Richard Bourke, who directs the center, declined to comment Thursday.

Theriot is being held at the Livingston Parish Detention Center without bond. The filings say Theriot is indigent and cannot afford a lawyer.

Follow Caroline Grueskin on Twitter, @cgrueskin.