Police Foil Jihadist Beheading Plot in Boston

"We believe the intent was to behead a police officer.... They were planning to act Tuesday."

The man shot and killed Tuesday by Boston police was plotting to behead a police officer, a law enforcement source told FoxNews.com.

The long military style blade Usaama Rahim pulled on police just before he was shot was similar to those seen in Islamic State group-produced videos of beheadings of captives in the Middle East.

Late on Tuesday the FBI arrested a man in connection with the case.David Wright, 25, appeared in U.S. District Court in Boston Wednesday to face conspiracy and terrorism-related charges, CNN reported. Wright allegedly attempted to destroy Rahim’s cell phone and conceal evidence of their plans.

"We believe the intent was to behead a police officer," one official told The Boston Globe. "We knew the plot had to be stopped. They were planning to take action Tuesday."

It’s another example of how homegrown terrorism may be a growing threat. ABC News reported:

The FBI had been tracking 26-year-old Usaama Rahim for several weeks, and authorities are looking into whether he may have been radicalized by ISIS propaganda online, law enforcement sources said.

Such radicalization "represents the newest element of the terrorist threat facing the country, where we have individuals who affiliate with terrorist ideologies but do not coordinate their operational activities with terrorist organizations," John Cohen, a former top Homeland Security official said on ABC News. "This poses the most significant counter-terrorism challenge" for U.S. authorities since the 9/11 attacks, Cohen added.

ABC said that law enforcement wanted to question Rahim after receiving "some terrorist-related information," according to Boston Police Commissioner William Evans. Specifically, Boston police and the FBI wanted to talk with Rahim "about his intentions in some other matters that we turned up," said Vincent Lisi, the head of the FBI’s Boston field office.

The FBI noted a recent change in Rahim’s behavior, including social media threats against police, which prompted them to try to approach him Tuesday, according to an official.

Coincidentally, the House of Representatives on Wednesday held a hearing on "Terrorism Gone Viral: The Attack in Garland, Texas and Beyond." U.S. intelligence officials are warning about the growing use of encrypted communication and private messaging by supporters of the Islamic State, according to NBC.