Investigators in Texas continued to hunt for a motive early Wednesday after a lone shooter entered Robb Elementary School in Uvalde and killed at least 19 students and two adults.

Lt. Chris Olivarez with the Texas Department of Public Safety (DPS) appeared on "America’s Newsroom" to give an update on what investigators have learned so far, and what questions still need answers surrounding the history and motive of 18-year-old shooter Salvador Ramos.

"We do know for a fact that there was no criminal history or no gang affiliation as well that would have set off any indicators for him to make this purchase [of a long rifle]," Olivarez said.

Police following the Texas school shooting

Police walk near Robb Elementary School following a shooting, Tuesday, May 24, 2022, in Uvalde, Texas. (AP Photo/Dario Lopez-Mills)

Olivarez confirmed that Ramos was in possession of one long rifle, but said investigators were still collecting evidence from the scene and working to learn more about the firearm’s capacity and how it was obtained.

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Ramos had attended a local school but appeared to be a loner, with Olivarez saying that investigators have yet to identify any friends or a girlfriend.

Olivarez said Ramos was unemployed and living with his grandparents in Uvalde, located about 85 miles west of San Antonio. He said it was unclear why and for how long he was living with them.

Law enforcement officials have said that Ramos shot his grandmother before driving to the school. 

Uvalde Texas school shooting families

People leave the Uvalde Civic Center following a shooting earlier in the day at Robb Elementary School, Tuesday, May 24, 2022, in Uvalde, Texas. (William Luther/The San Antonio Express-News via AP)

Olivarez said that the grandmother is in critical condition and could help investigators learn more about Ramos’ past and what set off the gunman to commit the mass shooting.

"So a lot of unanswered questions as to exactly what these indicators were, what were the motives behind this mass shooting … but also the indicators that caused him to shoot his own grandmother," the lieutenant said.

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Investigators were still searching for Ramos’ parents, according to Olivarez.

The Texas Rangers division of the DPS is leading the investigation.