The radical Muslim sect has shot police officials and clerics from atop motorcycles, torched churches and even freed hundreds in a brazen prison escape in Nigeria's restive north. But this week, Boko Haram expanded its reach and claimed its first suicide bombing in the capital of Africa's most populous nation.
Thursday's attack killed at least two people and sent a thick cloud of smoke into the sky that could be seen from across the capital. By striking at the national police headquarters in Abuja, analysts say the group is showing it is willing to spread its fight beyond Nigeria's Muslim-dominated north.
"This was a bold and deliberate statement on their part to announce that they have come to stay," said criminologist and security consultant Innocent Chukwuma.
Boko Haram, whose name in the local Hausa language means "Western education is sacrilege," has long campaigned for the implementation of strict Shariah law across Nigeria's northern states. The country's south is predominantly Christian.
The group is responsible for a rash of killings which have targeted security officers, politicians and clerics in Nigeria's northeast over the last year. But until recently, most attacks have been near the sect's stronghold of Maiduguri, about 540 miles (some 880 kilometers) from Abuja.
Author Shehu Sani, who wrote "The Killing Fields," an account of religious violence in Nigeria, says the government has long denied the severity of the situation.
"The truth is that Nigeria is engaged in a deadly Islamic insurgency which the authorities are continuously denying and downplaying," he said.
Western governments have previously expressed concern over Boko Haram, with the U.S. calling the group the "Nigerian Taliban" in a 2009 cable released last year by the WikiLeaks website.
The documents also expressed fear that Boko Haram was catching the attention of al-Qaida's north African branch.
In a leaflet attributed to the group and delivered to journalists Wednesday, Boko Haram claimed that some of its members had been trained in Somalia. The lack of an effective government there has allowed terror groups to operate freely.
"Very soon," the message said in Hausa, "we will wage Jihad on the enemies of God and His Prophet."
It became clear Boko Haram had broadened its reach in May, after a man who said he spoke for the group claimed responsibility for multiple blasts that hit beer gardens in two northern cities and a town near the capital, leaving 18 people dead. The May 29 attacks came hours after Nigeria inaugurated President Goodluck Jonathan.
Jonathan then expressed his readiness to negotiate with Nigeria's new crop of militants. Militancy in the country's oil-rich delta had already been appeased with a 2009 amnesty program. The governor of the state most affected by Boko Haram attacks made a similar offer to the sect.
But the group seemed unwilling to cooperate. In leaflet distributed June 12 and signed by a man called Usman Al-Zawahiri, they imposed a laundry list of conditions that they said needed to be met before they would enter talks the government. That list included the implementation of Shariah law in the north, the resignation of the newly elected state government and the prosecution of top officials who the group holds responsible for the death of Boko Haram leader Mohammed Yusuf, who died in police custody in 2009.
Shortly after those demands were made, Inspector General of Police Hafiz Ringim visited the Boko Haram stronghold of Maiduguri. During Tuesday's visit, he said the group's days were "numbered."
Two days later, the suicide bomber attacked just outside Ringim's office. A traffic warden was the only confirmed death, aside from the alleged bomber.
Jonathan, in a bid to reassure Nigerians, said Friday that "security agencies are on top of it," as he stood amid the wreckage in the parking lot of what many Nigerians consider a bastion of security.
He asked people not to panic, adding that such attacks would soon be "a thing of the past."
But people say they are not reassured.
"This was not an ordinary police station," said Chukwuma Awaegbu, a 36 year-old fashion designer in the commercial capital of Lagos. "It was the police headquarters for the whole country ... Anything can happen, anything, anytime, anywhere."
Nigerian security forces lack the tools to prevent serious security threats, said Chukwuma, the security consultant.
"Their reform has emphasized more on hardware at the expense of investment in intelligence-led approaches," he said.
In Maiduguri, residents say the police's heavy-handed approach is not working.
"The police should stop killing sect members," said 52-year-old Umaru Giwi on Saturday. "They should prosecute the arrested ones in court instead of killing them on the battlefield."
As security agencies struggle to fight back, analysts say Boko Haram's tactics keep evolving.
"Suicide bombing is a culture," said Olusegun Sotola, a researcher at the Lagos-based Institute for Public Policy Analysis. "It has become entrenched in other parts of the world, and it can take root here too."
Associated Press writer Njadvara Musa contributed to this report from Maiduguri.