In 1903, a young Christian Russian boy, Michael Ribalenko, was found murdered in the town of Dabossary (Dubasari in Romanian), about 25 miles north-east of Kishinev; the town is situated on the left bank of the river Dniester , and formally was not a part of Bessarabia. Although it was clear that the boy had been killed by a relative (who was later found), the government chose to call it a ritual murder plot by the Jews. The mobs were incited by Pavel Krushevan , the editor of the Russian Language Anti-Semitic newspaper "Bessarabian", and the vice-governor Ustrugov. They used the age-old calmny against the Jews (that the boy had been killed to use his blood  in preparation of matzo ).

Viacheslav Plehve, the Minister of Interior, supposedly gave orders not to stop the rioters. However the pogrom lasted for three days, without the intervention of the police. Forty seven (some say 49) Jews were killed, 92 severely wounded, 500 slightly wounded and over 700 houses destroyed. Despite a world outcry, only two men were sentenced to seven and five years and twenty-two were sentenced for one or two years. This program  is considered the first state-inspired action against Jews in the 20th century and was instrumental in convincing tens of thousands of Russian Jews to leave the Russian Empire and to the United States and Palestine.

Many of the younger Jews, including Mendel Portugali, made an effort to defend the community.
Source: http://en.wikipedia.org/wiki/History_of_the_Jews_in_Moldova