Minutes before a gunman walked into a Texas elementary school with an AR-15 rifle, he posted to Facebook that was going to shoot up the school, officials said Wednesday.

It was 18-year-old Salvador Ramos’ third post that day. In the first post, about a half hour before the deadly attack, Ramos wrote he was going to shoot his grandma. He then shot her in the face and posted again to say he’d shot his grandmother.

Authorities said Wednesday there was no “meaningful forewarning” of the shooting that left 19 children and two teachers dead, but there were some chilling posts on social media in the days before the massacre.

Days before the attack, an Instagram account investigators say apparently belonged to Ramos posted a photo of a hand holding an ammunition magazine. Ramos legally bought two AR-style rifles just days before attack. On the day Ramos bought his second weapon last week, his Instagram account carried a photo of two AR-style rifles.

In that post, Ramos apparently tagged another Instagram user, one with more than 10,000 followers, asking her to share the picture with her followers.

“I barely know you and u tag me in a picture with some guns,” replied the Instagram user, who has since removed her profile. “It’s just scary.”

On the morning of the attack, the account linked to the gunman replied: “I’m about to.”

Instagram confirmed to The Associated Press that it is working with law enforcement to review the account but declined to answer questions about the postings. Investigators are also looking at a separate account on TikTok, possibly belonging to the shooter, with a profile that reads: “Kids be scared IRL,” an acronym meaning “in real life.” The profile is not dated.

Ramos was reportedly a high school dropout, officials said. Investigators have not been able to identify any criminal history, but the teen may have had a juvenile record. There’s no known mental health history connected to Ramos.