The Israeli Kibbutz Movement has formally joined the search for Democratic presidential candidate Bernie Sanders’ Kibbutz he worked on back in the ’60’s.

To date, no reporter has been able to pin down which kibbutz Sanders volunteered at for almost 6 months in 1964, after his graduation from the University of Chicago.

On Thursday, the movement put out a plea on its Facebook page, urging readers and elder Israelis help locate the kibbutz.

In a message on its page, which has 14,324 followers, the movement writes: “Help us solve the mystery: Bernie Sanders, a candidate for the leadership of the Democratic Party in the U.S, volunteered in the sixties in a kibbutz, but he doesn’t remember the name of it… Sanders said once in an interview, that he was in the kibbutz for several months, approximately between the years 1966 to 1964 with his wife at the time, Deborah Shilling from Baltimore. As Sanders was interviewed about it at the past and now he aims to run for the presidency of the US – the question was brought up in the foreign and local media, but remained unsolved – We decided to use the collective kibbutz wisdom and find out: Where did Bernie volunteer? We invite you to share and tag kibbutz members who can help solve the mystery.”

h/t Haaretz