Police vehicles sit in front of a multistory home being searched by authorities on June 2, 2015, in Everett, Mass., in connection with a man shot and killed earlier in the day in Boston. The man, under surveillance by terrorism investigators, was killed after he lunged with a knife at a Boston police officer and an FBI agent
Steven Senneā€”AP
June 3, 2015 6:04 PM EDT

A man who was under constant surveillance before being fatally shot by authorities in Boston on Tuesday had initially planned to behead a person outside Massachusetts, according to an FBI affidavit filed on Wednesday, but changed his mind to “go after” the “boys in blue” instead.

Authorities say 26-year-old Usaamah Rahim was killed early Tuesday after being approached by law-enforcement officers in the Roslindale neighborhood and taking out a large knife he bought via Amazon.com before moving toward them. Rahim is said in the document to have discussed his plans with at least two people, including David Wright, also 26, who appeared in court on Wednesday. He was charged with conspiring to conceal evidence of Rahim’s plans.

Officials said Rahim was being kept under 24-hour surveillance after they received “terrorist-related information” about him, the Associated Press reports. Texas Representative Michael McCaul, chairman of the House Homeland Security Committee, said in a Wednesday hearing that Rahim was being investigated for “communicating with and spreading ISIS propaganda online,” referencing the militant group Islamic State of Iraq and Greater Syria. McCaul called the case “a reminder of the dangers posed by individuals radicalized through social media.”

Ibrahim Rahim, a brother of the deceased, claimed on his Facebook page that his brother was shot in the back while on the phone. In a rare move, officers showed a video to religious and civil rights leaders in a bid to prove that Rahim had, in fact, moved toward officers with a military-style knife. Authorities shot Rahim three times.

“What the video does reveal to us very clearly is that the individual was not on the cell phone, the individual was not shot in the back and that the information reported by others that that was the case was inaccurate,” Darnell Williams, president of the Urban League of Eastern Massachusetts, said at a news conference, CNN reports. He added that the video “150%” corroborates the police account.

Write to Eliana Dockterman at eliana.dockterman@time.com.

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