A 17-year-old classmate of one of the two people who carried out a massacre at a high school in suburban Sao Paulo was questioned and released Friday, Brazilian authorities said.
Police said Thursday that they were seeking a warrant for the arrest of the teenager on suspicion he took part in the planning for the attack at Raul Brasil high school in Suzano, a community of more than 285,000 people 60km (37mi) east of Sao Paulo city.
The youth, whose name is being withheld, appeared at the courthouse in Suzano accompanied by his mother and a police escort to ensure his safety.
He was released after giving a statement to a prosecutor.
The young man was a classmate of Guilherme Taucci Monteiro, 17, who carried out the attack along with 25-year-old former student Luiz Henrique de Castro.
The pair entered the high school Wednesday and began shooting, killing eight people and wounding a dozen others before taking their own lives.
A search of the unnamed teen's residence turned up notebooks with drawings inspired by violent videogames. Authorities also found records of online purchases possibly connected to the arsenal assembled by the perpetrators.
The owner of the parking lot where the murderers kept the car they rented to commit the crime told the police that a third young man accompanied the killers to the location several times in the days before the shooting.
"We have not confirmed that information and we are passing on the photograph of the adolescent to those responsible for the parking lot to confirm, but we have other data that make us believe that that individual participated, at least in the planning phase," Sao Paulo state police chief Ruy Ferraz Fontes said.
The shooters were apparently motivated by nothing beyond a desire for "recognition and notoriety," Fontes said Thursday.
The Suzano massacre has similarities to the one that occurred on April 20, 1999, at Columbine High School in the United States, where two students killed 12 of their classmates and a teacher and then committed suicide.
Police said they were evaluating the possibility that Monteiro and De Castro were incited to commit the crime by individuals or groups operating on the so-called Dark Web, an area of the Internet with Web sites that are not readily accessible to browsers and search engines.