Man Arrested in Boston after Terror Suspect Shot Dead

One man was arrested and a knife-wielding suspect shot dead in Boston in connection with an alleged terror plot targeting law enforcement and military personnel, police said Wednesday.

The U.S. attorney's office identified the suspect in custody as David Wright and said he would appear in a federal court on Wednesday.

Wright was arrested overnight after police and the FBI shot dead 26-year-old Usaama Rahim whom police said approached officers while brandishing a military-style knife outside a pharmacy Tuesday.

"Over the weeks we were getting information that military and law enforcement lives were at threat," Boston Police Commissioner William Evans told reporters.

Authorities put out "several notices about the threat of law enforcement and military bases being attacked" in recent weeks due to incoming intelligence, Evans said.

The FBI refused to comment on specific media reports that one or both suspects had conspired to behead a police officer.

"We believe the intent was to behead a police officer," The Boston Globe newspaper quoted one law enforcement official as saying.

A senior official warned last week that the United States launches a new investigation into suspected sympathizers of the Islamic State extremist group in Iraq and Syria almost every day.

But Rahim's brother, imam Ibrahim Rahim, called the official account into question, alleging on social media that his younger brother was shot three times in the back as he waited for the bus.

A Muslim community leader, who was shown a video of the incident by police and the FBI, said the footage was inconclusive but expressed doubts over the family's account.

"It was not at a bus stop. He was not shot in the back," said imam Abdullah Faaruuq.

It was not clear what happened and the knife was not visible but "he was approaching them. They did back up," Faaruuq said.

Evans said the video showed five law enforcement officers retreating with their hands up, and that witness and officer accounts had detailed commands on the suspect to drop his weapon.

"You see them go a good 15 yards with a threat coming at them. We can all agree. The weaponry is not clear, but with five officers coming at them, there was no doubt in the video," said Evans.