Speculation continues to swirl around the motives and perpetrators behind the bombing at the Boston Marathon, which took the lives of at least three people and injured more than 170 others, according to The New York Times.

So far, authorities haven’t gathered enough evidence to arrest possible suspects of the attacks.

“Any time bombs are used to target innocent civilians, it is an act of terror,” President Barack Obama said during a White House press conference on Tuesday. “What we don’t yet know, however, is who carried out this attack, or why, whether it was planned and executed by a terrorist organization—foreign or domestic—or was the act of a malevolent individual.”

Some experts suggest anti-government “patriot” groups may be behind the bombings. Jessica Stern, a terrorism expert at Harvard University, told Yahoo! News the date of the attack coincided with both Tax Day and Patriots’ Day, suggesting right-wing extremist groups may have been involved. She went on to say April is a prevalant month for extremist group activity. The 1995 Oklahoma City bombing, 1999 Columbine High School shooting and 1985 police raid in which authorities overtook a compound run by a group called The Covenant, the Sword and the Arm of the Lord all took place in April.

However, other experts, including Mark Potok, a senior fellow at the Southern Poverty Law Center, says extremist groups tend to target clear subgroups such as the government, Muslims, immigrants, gays or black people. The Boston bombings didn’t target a specific group.

As the investigation surrounding the bombings continues, officials remind the public—and press—not to jump to conclusions.

“The problem you have in the White House is that the hunger and demand for information from the press is always going to outpace your investigation,” National Security Council spokesman Tommy Vietor told ABC News. “But there’s no upside to rushing.”