(CNN) - As Congress begins to tackle immigration reform, a new poll indicates there's been a drop in support over the last month for a pathway to citizenship for undocumented immigrants.
According to a Quinnipiac University survey released Thursday, 52% favor such a proposal in the new poll, down from 59% who said the same thing in an April 4 survey, taken before the Boston Marathon bombings.
It's unclear whether the decline is directly related to last month's terror attack, but the same Quinnipiac poll also indicates the bombings had an influence on some voters' opinions about immigration reform. Nearly one in four voters said the bombings caused them to change their minds about whether undocumented workers should get a pathway to citizenship, according to the poll.
However, a strong majority–70%–say the terror attack is not a factor in their personal view about immigration.
When asked whether creating a pathway to citizenship for undocumented immigrants would increase the likelihood of terrorism, 22% say yes, while 66% say it would not make a difference.
Authorities allege the attacks were carried out about by Dzokhar and Tamerlan Tsarnaev, two brothers who entered the country legally from Kazakhstan last decade. Dzokhar, the youngest brother, became a U.S. citizen last year.
But concerns about the brothers' ties to the North Caucasus region in Russia found their way into the political debate, as some lawmakers have called for hearings over how the two brothers' intentions slipped through the cracks of the U.S. intelligence community.
Other lawmakers, meanwhile, have suggested taking more time in the immigration bill debate as the investigation continues and as emotions remain high in the wake of the terror attack.
A bipartisan group of senators formally unveiled their immigration proposal last month, which calls for tighter border security and a 13-year path to citizenship for those who entered the United States illegally before 2012. Included in that path is a requirement to pay a fine and back taxes, as well as pass a background check.
Senators who have been working on the bill, including Republican Sen. John McCain and Democratic Sen. Chuck Schumer, say if anything, the immigration bill will boost efforts to make the country more secure.
A separate poll released Wednesday by the Pew Research Center indicates that most see the Boston attacks as separate from the immigration debate. While a little more than a third of Americans–36%–say Boston should be an important factor in immigration reform efforts, a majority–58%–say the two are separate issues.
Many, however, have yet to form an opinion about the Senate immigration bill, the Pew poll shows. While 33% favor it and 28% oppose the legislation, 38% say they don't know enough about it to form an opinion.
Quinnipiac interviewed 1,147 registered voters by telephone from April 25-29, with a sampling error of plus or minus 2.6 percentage points.
For the Pew survey, 1,003 adults were interviewed by telephone from April 25-28. The sampling error is plus or minus 3.7 percentage points.