BOULDER, Colo. -- University of Colorado football coach Gary Barnett said Friday afternoon that he'll punish the players who brought about a four-month rape investigation that ended with no charges filed.

Barnett said that four unidentified players violated conduct standards. It wasn't immediately clear if they were the same four players implicated as possible suspects.

Boulder prosecutors said Friday that they will not file sexual assault charges in connection with the alleged rape at a party attended by football players and recruits.

Boulder District Attorney Mary Keenan said that after weighing the evidence, prosecutors decided that there was not enough evidence to proceed with a successful prosecution.

"This decision is not a reflection of the credibility of the victim and should not be construed as such by anyone. It is a reflection of the many difficulties frequently encountered in prosecutions of acquaintance rape," Keenan said in a press release.

A college student claimed that she was gang raped at a Dec. 7 off-campus party for recruits. Six CU players and about 15 high school recruits were at the party, which was hosted by four women not affiliated with the athletic department.

According to some who were there, alcohol was available at the party.

In all, 28 DNA specimens were submitted last month as part of the lengthy investigation that took Boulder police to California and Texas.

Keenan said that the statute of limitations on sexual assault charges are 10 years, and that prosecutors could proceed with charges in the future should they get additional evidence.

Police officers and the district attorney's office are in the process of evaluating the evidence to determine if it supports other charges, such as providing alcohol to minors, drug use and theft of property.