The 19-year-old main suspect in the alleged foiled terrorist plot to attack Taylor Swift concerts in Austria this week had grown a long beard and became a "bit unusual" in the leadup to his arrest, his neighbors are revealing. 

The suspect, identified in Austrian media as Beran A., hailed from Ternitz, a town about 50 miles southwest of Vienna, according to Reuters. Locals there told the news agency that he had started to become more serious in recent weeks and was growing out his facial hair. 

"Only recently did he become a bit unusual," Nicole Morgenbesser, a 33-year-old mother who lived near him, explained to Reuters. 

Morgenbesser said the suspect with North Macedonian roots always said hello to her on the street or waved to her from his car until about a few weeks ago, when "he stopped greeting me." 

TAYLOR SWIFT TERROR PLOT INVESTIGATORS DETAIN THIRD SUSPECT, AN IRAQI 18-YEAR-OLD LOYAL TO ISIS 

Suspect in alleged plot to attack Taylor Swift concerts

A screen displays a photo of a man arrested in connection with an alleged terrorist plot targeting Taylor Swift concerts this week in Vienna, Austria, that has now been postponed.  (Roland Schlager/APA/AFP via Getty Images)

On Wednesday morning, the suspect was arrested by police before his home was raided, Reuters reports. 

Neighbors told the news agency that the suspect’s parents were not around at the time of the operation and that locals were informed by police that there was a gas leak so they would leave their homes.

Inside the house where the suspect lived, officials say they found chemical substances and technical devices. 

TAYLOR SWIFT TERROR PLOT SUSPECT WHO PLEDGED ALLEGIANCE TO ISIS HAD CHEMICAL SUBSTANCES, DEVICES AT HOME 

Ternitz, Austria homes

A view of the area where the main suspect lived in Ternitz, Austria, following the cancelation of three Taylor Swift concerts in Vienna after the government confirmed a plot to attack the venue. (Reuters/Elisabeth Mandl)

"He wanted to carry out an attack in the area outside the stadium, killing as many people as possible using the knives or even using the explosive devices he had made," Omar Haijawi-Pirchner, the head of the Directorate of State Security and Intelligence, said on Thursday. 

Haijawi-Pirchner added that the suspect was "clearly radicalized in the direction of the Islamic State and thinks it is right to kill infidels." 

Franz Ruf, the public security director at Austria’s Interior Ministry, told public broadcaster ORF on Thursday that the 19-year-old suspect had uploaded an oath of allegiance to ISIS on an internet account a few weeks ago.  

Ternitz Mayor Christian Samwald told Reuters that "you always hear about these sort of things, but it's something else when this happens on your own front door." 

Taylor Swift performing on stage

Taylor Swift performs onstage during The Eras Tour at Olympiastadion on July 27, in Munich, Germany.  (Thomas Niedermueller/TAS24/Getty Images for TAS Rights Management)

CLICK HERE TO GET THE FOX NEWS APP 

"The lesson is it's difficult to prevent someone from being radicalized on the Internet," he added. 

The Associated Press contributed to this report.