(Adds details on board meeting)

By Cassandra Garrison and Andrea Shalal

MEXICO CITY/WASHINGTON, Sept 19 (Reuters) - The Inter-American Development Bank's board on Monday reviewed an independent report showing evidence of some allegations made by a whistleblower against the bank's chief, Mauricio Claver-Carone, according to a source with knowledge of the matter.

The Washington-headquartered lender, Latin America's main development bank, hired legal firm Davis Polk to investigate the allegations made against Claver-Carone in a whistleblower email in April, including an intimate relationship with a staffer and misuse of funds.

Reuters reported in April that the whistleblower had sent an anonymous email to the board of directors and the bank's ethics officer, accusing Claver-Carone, a former Trump administration official, of conducting a relationship with a senior strategist who reported to him, and of misusing bank funds.

Claver-Carone denied the allegations in April and said he was the target of an "anonymous political media campaign." In New York on Monday for meetings on the sidelines of the United Nations General Assembly, Claver-Carone did not immediately respond to a request for comment.

The board of directors met to review the Davis Polk report on Monday, according to the source with knowledge of the meeting and another person briefed on the matter. These people declined to be identified, citing sensitivities around the situation.

The firm, in a presentation to the board of directors, said it had found evidence of some - but not all - of the allegations, according to the source with knowledge of the meeting. It was not immediately clear which allegations had been supported by the investigation.

The firm also told directors it had come up against a "lack of cooperation" from some participants in the probe, the source added, without giving more details.

The board had offered to share the investigation's findings with Claver-Carone before they were presented to the board on Monday, but only under certain conditions, including that no retaliatory action be taken against participants in the investigation. Claver-Carone declined, the source said.

Claver-Carone wanted to be able to comment on the report before it was finalized and felt he was not given adequate time to reply, the source added.

An IDB official who works closely with Claver-Carone told Reuters that Claver-Carone had not received or seen a copy of the report before the board meeting, despite repeated requests from his attorneys.