Several days ago, after the recent Nevada caucuses, the Barack Obama campaign called for an investigation into what happened at some of the caucus locations throughout the state. According to a press conference held by the Obama campaign, “an indeterminate number of caucus locations” stopped allowing new voters in at 11:30am, half an hour before the caucuses were actually supposed to start at 12:00pm. This is allegedly because of incorrect information provided by the Clinton campaign in their manuals.
The Obama campaign is not going to challenge the outcome of the vote, even though Clinton got more delegates than Obama.
According to a statement sent out by the Obama campaign to its volunteers, there were over 200 incidents at caucus sites. Although they didn't blame these on the Clinton campaign, they did mention that they had extra impact because of and with “an entire week’s worth of false, divisive, attacks designed to mislead caucus-goers and discredit the caucus itself” from the Clinton campaign.
Other caucus sites ran out of paper ballots, registration forms, and other things, and apparently there were some ballots that had been pre-marked for Clinton.