A leading human rights group has suspended its senior military analyst following revelations that he is an avid collector of Nazi memorabilia.

The group, Human Rights Watch, had initially thrown its full support behind the analyst, Marc Garlasco, when the news of his hobby came out last week. On Monday night, the group shifted course and suspended him with pay, “pending an investigation,” said Carroll Bogert, the group’s associate director.

“We have questions about whether we have learned everything we need to know,” she said.

The suspension comes at a time of heightened tension between, on one side, the new Israeli government and its allies on the right, and the other side, human rights organizations that have been critical of Israel. In recent months, the government has pledged an aggressive approach toward the groups to discredit what they argue is bias and error.

Injected suddenly into that heated conflict, word of Mr. Garlasco’s interest seemed startling to many. The disclosure ricocheted across the Internet: Mr. Garlasco, an American, was not only a collector, he has written a book, more than 400 pages long, about Nazi-era medals. His hobby, inspired he said by a German grandfather conscripted into Hitler’s army, was revealed on a pro-Israel blog, Mere Rhetoric, which quoted his enthusiastic postings on collector sites under the pseudonym “Flak88”  including, “That is so cool! The leather SS jacket makes my blood go cold it is so COOL!”