ROSLINDALE (CBS) - A 26-year-old man shot and killed by officers in Boston Tuesday morning was under investigation for threats against law enforcement, CBS News reports.
A law enforcement source told CBS News that the investigation is consistent with the threat stream being tracked by the FBI that ISIS is urging attacks against law enforcement and military personnel by any means available.
I-Team: Targeting Homegrown Radicals
The Federal Law Enforcement source says Usaamah Rahim, of Roslindale, had been on investigators' radar for several months and recently became radicalized and inspired by ISIS' online propaganda.
According to the source, Rahim "started to act differently" on Tuesday. Investigators did not have an arrest warrant but wanted to question him. The source says Rahim was about to get on a bus, and members of the Joint Terrorism Task Force wanted to prevent that from happening.
Video from a nearby restaurant showed the confrontation.
Earlier Tuesday, officials said the investigation into Rahim was "terrorist-related."
Officials said there's no current threat to the public, but another man was arrested in Everett and a home in Warwick, Rhode Island was searched in connection with the investigation.
Boston Police commissioner Bill Evans told reporters Boston police and the FBI were watching the man around 7 a.m. near the CVS in the Stony Brook Plaza on Washington Street when they confronted him to speak with him.
RAW VIDEO: Police, FBI News Conference
Evans said law enforcement officials did not have their guns drawn when they approached Rahim.
At that point, Evans said, Rahim pulled out a "military-style knife," and officers believed their lives were in danger.
Evans said officers gave Rahim several commands to put the knife down and when he came closer to them, both Boston Police and an FBI agent fired their weapons.
Jennifer Wicks, the Litigation Director for the Council on American Islamic Relations says, "Our organization is concerned about what happened and what led to the death of this man."
Surveillance video apparently shows officers backing away from Rahim, who was holding the knife, Suffolk County District Attorney Dan Conley told reporters Tuesday. Boston Police say they will show the surveillance video of the shooting to the Boston Islamic Society on Wednesday.
A witness told WBZ-TV at least three shots were heard.
Officials said Rahim was shot twice. He was rushed to Brigham and Women's Hospital where he died.
Conley said the shooting is under investigation.
"At that time he was considered to be armed and dangerous," Vincent Lisi, FBI special agent in charge said at a press conference Tuesday.
According to investigators, Rahim had been under 24-hour surveillance by the joint terrorism task force for the last several weeks.
Evans did not elaborate on why Rahim was being watched.
No law enforcement officers were hurt in the shooting and their names were not released.
Investigators arrived at a triple-decker building on Linden Street in Everett Tuesday morning. About 10 hours later, a man, later identified as David Wright, was taken out of the house and arrested by State Police and Boston Police.
Wright is expected to appear in U.S. District Court in South Boston on Wednesday, but specific charges have not been released yet.
WBZ-TV's Jim Armstrong reports
Boston Police say the arrest is connected to the investigation in Roslindale.
Neighbors say they never noticed anything strange about the building.
WARWICK, RI INVESTIGATION
Shortly after the shooting in Boston, federal agents with the support of RI State Police showed up at a home on Aspinet Drive in Warwick. Neighbors say officers went into the home with their weapons drawn, but no shots were fired.
WBZ-TV's Bill Shields Reports
Neighbors say a man in his late 20's has lived in the house for quite some time. According to neighbors, the man recently grew a beard, and started wearing robes and acting strange. It is unclear if anyone was taken into custody at the home.
WPRI reports that the investigation at the home in Warwick's Gaspee Point neighborhood is connected to the anti-terror investigation.
ED DAVIS REACTION
WBZ Security Analyst Ed Davis says the situation is troubling.
"We hear these things coming out of the Middle East all the time but to have something so close to our homes manifest itself like this is certainly concerning," Davis said.
Davis, who was Boston Police Commissioner during the marathon bombings, says police must know a lot more than they are telling the public.
Watch: Ed Davis On Terror Probe
"I know personally that you don't put this kind of 24 hour, seven day a week surveillance on people unless you have a significant worry and a significant amount of information that they're up to something dangerous so everything would indicate that this is an unfolding plot," Davis said.
"This has all the classic indications of rolling up a terrorist plot and a cell that has gone active."
WBZ NewsRadio 1030's Karen Twomey reports
for more features.