Given the following context:

Paul Helfeld (also given as Hefeld), aged 21 in 1909, and Jacob Lepidus (also reported as Lapidus), who was 25 the same year, were Jewish-Latvian immigrants. They had been members of the Latvian Socialist Party and, although they had not held positions of responsibility, they had smuggled revolutionary literature into Russia for the party. The pair had been living in Paris in 1907, along with Lepidus's brother Paul, a revolutionary bomber who went under the nom de guerre "Strygia"; Jacob was described in The Times as a "member of a notorious Russian revolutionary family". On 1 May 1907 Paul Lepidus was killed when a bomb he was carrying to assassinate Armand Fallières, the President of France, exploded prematurely. Lepidus and Helfeld fled the country and lived in Scotland for a year, before moving to Tottenham.Both men joined a small group of Latvian agitators living in north London; according to other members of the group, the pair had criminal records and had joined as a cover for the robberies they carried out. Lepidus was employed, briefly, at a furniture factory, while Helfeld took a job at the Schnurmann rubber factory in Tottenham. Helfeld refused to give his name when he joined the company, so he was listed on the time sheets as "Elephant" in reference to his bulk. Situated on the corner of Tottenham High Road and Chesnut Road, the factory sat opposite Tottenham Police Station, which was under the control of the Metropolitan Police.Special Branch suspected another individual, the Russian revolutionary Christian Salnish, of having organised the robbery. Salnish, who often went under the name Jacob Fogel, had been an active revolutionary since the age of 13. He participated in the 1905 Russian Revolution and afterwards helped to build resistance groups in the Baltic states and Saint Petersburg, then the capital of Imperial Russia. Special Branch suspected a political element to the crime based on Salnish's involvement, but as both Helfeld and Lepidus died during the chase, the motivation for the crime...

answer the following question:

What was the last name of the person who was described in The Times as a "member of a notorious Russian revolutionary family?" 

Lepidus