Man being followed by Joint Terrorism Task Force fatally shot by Boston police officer, FBI agent

A man under 24-hour surveillance by anti-terrorism investigators was shot and fatally wounded by a Boston police officer and an FBI agent Tuesday morning as he threatened them with a large, military knife, authorities said.

Usaama Rahim, 26, was approached in Boston’s Roslindale neighborhood as part of an “investigation that’s been going on for some time by the Joint Terrorism Task Force,’’ Police Commissioner William B. Evans said at a news conference Tuesday afternoon.

“We believed he was a threat,’’ Evans said. “He was someone we were watching for quite a time. The level of alarm brought us to question him today. I don’t think anybody expected the reaction we got out of him.’’

Evans said officers retreated when Rahim approached with the knife. With their lives in danger, they fired, hitting Rahim with two bullets, one to the torso and one to the abdomen, he said.

Vincent Lisi, head of the Boston FBI, would not disclose any specifics of why Rahim was being investigated.

He said, “I can tell you that our investigation is still ongoing. There’s a lot more for us to do.’’ He would not comment on whether other people are being looked at in the investigation.

He said Rahim was considered “armed and dangerous’’ at the time he was confronted, but “we don’t think there’s any concern for public safety right now’’ from other suspects.

Suffolk District Attorney Daniel F. Conley said his office would investigate to determine whether the officer and agent were justified in using deadly force. While stressing that no final conclusion has been reached yet, Conley said the incident was captured by surveillance video, which appeared to show Rahim was the aggressor.

The law enforcement officials had their weapons holstered when they first approached him and only pulled their guns when Rahim armed himself with a large knife, Conley said.

“The officers approached this individual without their firearms drawn,’’ Conley said. “It was this deceased person who drew that knife. It appears [law enforcement officials were] backing away before they exercised deadly force.’’

Evans displayed a large photograph of the long, deadly-looking knife at the news conference.

Police said that the deadly encounter happened near the CVS parking lot on Washington Street at 6:59 a.m.

Rahim was rushed to Brigham and Women’s Hospital, where he was later pronounced dead, police said.

The officer and the agent were taken to Boston hospitals to be examined for stress, but they did not suffer physical injuries, police said.

Investigators searched an apartment building Tuesday on nearby Blue Ledge Drive as part of their investigation, but officials would not say how it was connected to the incident.

In another development, Everett police were assisting the FBI with an investigation in that city, police said. Authorities said the activity was related to the Roslindale investigation.

A woman who said she was acquainted with Rahim and his wife, said, “He and his wife, they are good people. They definitely kept to themselves.’’

The woman, who said she did not want to give her name because she did not know the couple that well, said in a telephone interview, “There is nothing that I can think [of] that warrants him being investigated or followed at 7 o’clock in the morning.’’

“It’s really scary,’’ said the woman, who said she met Rahim and his wife at the Islamic Society of Boston in Roxbury. “It’s literally hitting too close to home.’’

Before officials publicly identified Rahim, his older brother, Imam Ibrahim Rahim, used social media to announce his younger brother’s death. The elder Rahim wrote that his brother was waiting at a bus stop when law enforcement approached and that Usaama Rahim called their father on his cellphone so he could be a witness to the confrontation.

The elder Rahim said his brother was shot three times in the back by Boston police officers and that his last words were, “I can’t breathe.’’

Later Tuesday, the elder Rahim posted on Facebook that his family would not have an immediate comment.

“We are deeply grieved by the loss of my younger brother,’’ Ibrahim Rahim wrote. “While we understand the need for information. We ask that the press give us time to grieve. We will have a statement once we have met as a family.’’