Mor than half of American voters support a criminal investigation of Democratic presidential candidate Hillary Clinton's use of a personal email account when she was U.S. secretary of state, said a Monmouth University poll released Wednesday. Despite those findings, a majority of voters also believe that the use of her personal account was mainly a matter of convenience. Still, Clinton, as well as Republican presidential candidate Donald Trump, had the highest negative ratings among independent voters.

Fifty-two percent of registered voters said Clinton's emails should be subject to a criminal probe for the potential release of classified material, according to the poll, while 41 percent were not in favor of a legal investigation. Eighty-two percent of Republicans and 56 percent of independent voters support an investigation, while 66 percent of Democrats were opposed.

However, only 38 percent of registered voters said Clinton's private email account suggested that she had something to hide, with the majority, 51 percent, feeling that its use mainly had to do with overall convenience. Most Democrats -- and nearly half, 48 percent, of independents -- did not think that there was anything particularly suspicious in Clinton's private email use.

"Initial media reports of a criminal probe proved to be inaccurate," Patrick Murphy, director of the Monmouth University Polling Institute in West Long Branch, New Jersey, said in a statement. "But most voters feel that the potential release of classified information merits investigation." A July 23 article in the New York Times mistakenly claimed that federal inspectors had asked the Justice Department to open an investigation into Clinton's personal email account. 

The poll also confirmed that more voters have unfavorable impressions of both Clinton and Trump, despite both candidates' polling leads in their respective political parties. Only 27 percent of independent voters have favorable impressions of Clinton and 30 percent for Trump, compared to 52 percent and 54 percent, respectively, suggesting that both candidates remain polarizing figures. Overall, however, Clinton has the highest favorability ratings of all presidential contenders among registered voters, at 38 percent. Former Florida Gov. Jeb Bush, a Republican, placed second with 33 percent.

A new Franklin Pierce University/Boston Herald poll released Tuesday suggested that Sen. Bernie Sanders has surged past Clinton among likely voters in New Hampshire's Democratic primary, with 44 percent supporting Sanders compared to 37 for Clinton, although she maintains a solid lead in national polls. 

The Monmouth University poll, conducted among 1,003 registered voters before the first Republican primary debate last week, has a 3.1 percent margin of error.