Steele was arrested about 11 p.m. in Fort Worth. He is believed to be homeless and was staying in a vacant building, where investigators found things that could be used to make the bombs, including bottles, lighter fluid and fuses.
He was being charged with one felony count of arson of an occupied building and held on a $50,000 bond, Fort Worth Fire Capt. Tom Crow told TPM.
Steele (pictured at right) had apparently visited Davis' office twice in recent days, once on Friday and again on Monday.
An affidavit that police released on Wednesday afternoon said that he wanted to talk to the senator about a "tazing incident that occurred in Michigan."
During one of the visits, according to the document, Steele gave the staffers part of a dead animal and told them "it was a new species" and he wanted Davis to see it.
"He told staffers that they would be 'hearing about him in the news,'" Crow said. "And it turns out he was right. He was in the news."
Generally, Steele appeared to be suffering from mental health issues and was "not making sense" when he spoke, Crow said.
After his arrest, according to the affidavit, Steele made more comments about an alien species and told them he was keeping "another piece of the alien" in the rafters of a vacant building where he had been staying. Police asked the owner of the building if they could search the location and that's where they found materials for the explosives.
The attack took place at about 4 p.m., local time, on Tuesday. Staffers reportedly heard a loud thud and then opened the door to see waist-high flames.
Davis was not in the office at the time, but two staffers who were quickly went into action. One grabbed a fire extinguisher and put out the blaze.
Previously, authorities said the suspect had thrown two Molotov cocktails at the door. But the affidavit released by the Fort Worth Police Department said that Steele put six Molotov cocktails in a paper bag, lit the bag and threw the whole thing at the door.
The document said the fire not only burned the wooden door but also melted the lower part of the Texas state seal mounted high on the front of the door.
Digital interactive specialist Ryan Cormier was working in his office at Ratio Digital, about 30 feet down the hall, when the fire alarm went off. In an email, he told TPM he was quickly hit with the overwhelming smell of lighter fluid. Then he saw smoke in the hallway.
"When I exited the office and turned right, I saw a few people standing in the hallway, and a ball of flames in front of the Senator's office," Cormier wrote. He witnessed Davis' staffer put out the fire. "This all happened very fast."
On his way out of the building, Cormier noticed a sweatshirt and a pair of track pants littered in the stairwell of the building. He said he believed the suspect had taken off the clothing as he fled.
Cormier said a valet in the building spotted the man fleeing and tried to catch him. "He actually chased him a good distance, but the guy was able to escape around the side of the building and down the train tracks behind the office."
More than an hour after the fire, Cormier was able to get back in the building and snap a couple photos of the scene with his phone. In one, a charred pile of clutter can be seen on the hallway floor outside the senator's office. In the other (shown at right), the burned door of the office is open and a chunk of carpet in the hallway had been removed.
"I absolutely could not get the smell of lighter fluid out of my head, and it actually made me feel a bit nauseous," he wrote. "I had a headache for a few hours after the incident."
As far as he knew, Cormier said there were no threats or advanced warning that an attack would be taking place. But during the aftermath, he said he heard the senator's staffers talking about something unusual happening recently.
"I overhead two of the women from the Senator's office saying that the suspect had come by recently, and made them very uncomfortable," Cormier wrote to TPM. "I didn't get the entire story, but apparently he came by with some object or substance which 'contained a brand new form of life,' or something to that effect. It sounds to me like this individual is probably battling some mental issues."
At a news conference on Tuesday night, Davis told reporters that Texas state troopers put her on lockdown for about four hours while they ensured that she was not in danger.
In prepared remarks her spokesman sent to TPM, Davis said at the time that she did not know what the attackers motive was but that she would not back down from her support of the issues that she cares about, including education, jobs and women's healthcare.
She also invoked last year's shooting of former Congresswoman Gabrielle Giffords. The Arizona Democrat was wounded and six others were killed at a "Congress on Your Corner" event she was holding in Tucson.
"As these violent incidents happen across the country, it should remind us of the importance of the democratic process and remind us to keep a sense of civility even as we disagree," Davis said in the prepared remarks. "Acts of violence are never a solution and have no place in our society."
Indeed, details that emerged on Wednesday made the circumstances of the firebombing attack sound even more similar to the Tucson shooting.
In the Arizona case, the suspect, Jared Loughner, was schizophrenic with a long history of strange behavior. He had also visited the congresswoman at an event prior to the attack, hoping to speak with her.