A man accused of plotting a “violent attack” on the Texas Capitol in Austin is in custody after state authorities say they received a tip about the alleged threat and worked through the night to track down a suspect.

The Texas State Department of Public Safety and the FBI thwarted a “credible threat” against the state capitol, according to a notice sent to Texas state senators Wednesday and reviewed by ABC News. The alleged attack was to occur on Thursday, according to the notice and Texas DPS.

Texas DPS said it learned of the threat Tuesday evening. Special agents worked alongside the FBI and local partners before arresting 40-year-old Benny Caldera Jr., whom it called the “main suspect,” at his residence in Converse, Texas, at around 3 a.m. Wednesday.

Caldera was transported to the Bexar County jail and has been charged with felony terroristic threat against a public servant, according to Texas DPS.

According to an official briefed on the investigation, the suspect had allegedly been threatening to conduct a mass shooting at the Texas Capitol on Thursday and had been collecting ammo and had guns.

Authorities were notified by people who knew the man that he has been growing more angry and potentially violent recently, the official said. Neither Caldera nor his wife are cooperating with the probe at this point, the official said, but other family members and co-workers are talking to investigators.

In recent weeks, the suspect had voiced anger over the state and direction of the country and the Palestinian cause, among other things, the official said. He also allegedly had been doing drugs more heavily.

Investigators are working to obtain search warrants for the suspect’s devices to determine if he had any accomplices or co-conspirators and what significance Thursday’s date has, according to the official.

FBI Director Kash Patel commended the investigation, calling the work of Texas DPS “outstanding.”

“Threaten Americans or our institutions and law enforcement will move FAST,” he said in a post on social media.

In the notice to state senators, Texas State Senate Secretary Patsy Spaw said the alleged threat was not cause for concern but that she wanted to let members know about it.

“The investigation is ongoing, and there is and will continue to be an enhanced DPS presence at the Capitol,” Spaw wrote in the notice.