By Aruna Viswanatha

WASHINGTON (Reuters) - An Obama administration task force probing misconduct that fueled the financial crisis is increasing its ranks, adding five financial analysts and 10 new federal prosecutors spread across the country, according to a senior Justice Department official.

The increased staffing reflects a new push by the administration to aggressively pursue cases against firms and individuals who contributed to the 2007-2009 financial crisis, especially ahead of the November election.

The U.S. Justice Department has so far brought few cases against high-profile targets since the crash.

The department closed criminal investigations without bringing charges against firms whose names are closely tied to the 2008 crash, including AIG and Countrywide.

Individual Wall Street players have largely escaped prosecution, after the Justice Department lost its first criminal case against two former Bear Stearns hedge fund managers in 2009.

U.S. enforcement authorities have asked for patience, saying financial crisis cases are complex and though the behavior may look bad, it doesn't always amount to outright fraud.

The task force formed earlier this year represents a more coordinated effort than prior investigations, the Justice Department official said in an interview on Thursday. Prosecutors are reviewing documents for both federal and state law violations.

In addition to the 50 positions the department previously announced, the DOJ is hiring 10 new assistant U.S. attorneys in districts that include Massachusetts and Colorado, according to job listings on the agency's website.

The department is also hiring five financial analysts and auditors to help understand and identify evidence, the official, who declined to be named, said.

It is also focused on civil laws, including a little-used federal statute called FIRREA, which may make such cases easier to bring. Continued...