By Jenna Zucker and Gabriella Borter
BUFFALO, N.Y. (Reuters) -An investigation into the weekend shooting of 13 people in Buffalo, New York, turned on Monday to a visit police said the suspect made to the city in March and whether warning signs were missed, as public figures decried the suspect's racist ideology.
Authorities said Payton Gendron, 18, who is white, carried out an act of "racially motivated violent extremism" when he opened fire with a semi-automatic rifle on Saturday at the Tops Friendly Market in a predominantly African-American neighborhood of Buffalo, where 11 of the 13 people struck by gunfire were Black.
Gendron, who police said surrendered to officers who confronted him inside the store, has been jailed without bond on a charge of first-degree murder. He entered a plea of not guilty.
Investigators have said they are searching through phone records, computers and online postings, as well as physical evidence, as new details about the suspect's past and meticulous planning emerge.
The Washington Post reported on Monday that the suspect, a resident of a southern New York state town hours away by car, made a trip to the Tops store in March to map its layout in preparation for the attack. He was confronted there at the time by a store security guard, who thought he looked suspicious, according to the Post.
Buffalo Police Commissioner Joseph Gramaglia told reporters at a news briefing on Monday that the suspect had paid a visit to Buffalo in early March, but he declined to confirm other details of the investigation reported by the Washington Post or other news media.
The Post said the planning trip to Buffalo was described in a 589-page document posted online by someone who identified himself as Gendron. The document is no longer available publicly, the Post reported.
The document referred to the Tops store as "attack area 1" and described two other nearby locations as attack areas to "shoot all blacks," the Post reported. Gendron counted that there were 53 Black people and six white people in the Tops at the time of his visit, according to the account.
Police confirmed that they are investigating Gendron's online postings, which included a 180-page manifesto he was believed to have written outlining the "Great Replacement Theory," a racist conspiracy theory that white people were being replaced by minorities in the United States and elsewhere.
"The evidence that we have uncovered so far makes no mistake this is an absolute racist hate crime that will be prosecuted as a hate crime," Gramaglia told reporters on Sunday.
Experts say the trend of mostly young white men being inspired by previous racist gun massacres is on the rise, citing recent mass shootings, including the 2015 attack at a Black church in Charleston, South Carolina, a 2018 shooting at a synagogue in Pittsburgh and a 2019 attack at a Walmart in an Hispanic neighborhood of El Paso.
President Joe Biden and his wife Jill Biden plan to visit Buffalo on Tuesday.
(Reporting by Jenna Zucker in Buffalo, New York; Additional reporting by Brendan O'Brien, Kanishka Singh, Doina Chiacu, Sarah N. Lynch, Gabriella Borter, Ken Li and Tyler Clifford; Editing by Jonathan Oatis and Rosalba O'Brien)