Question: what was the nationality of both David Berman and Bugsy Siegel ? 

Context paragraphs:
The Bugs and Meyer Mob: The Bugs (Bugsy) and Meyer Mob was a Jewish-American street gang in Manhattan, New York City's Lower East Side.  It was formed and headed by mobsters Bugsy Siegel and Meyer Lansky during their teenage years shortly after the start of Prohibition.  The Bugs and Meyer mob acted as a predecessor to Murder, Inc.

Harry Greenberg: Harry Schachter or Harry "Big Greenie" Greenberg was an associate and childhood friend of Bugsy Siegel, and an employee of both Charlie "Lucky" Luciano and Meyer Lansky.  On November 22, 1939, Greenberg was murdered by Bugsy Siegel and Whitey Krakow.  Siegel was eventually tried for the murders of Greenberg and Krakow, but was not convicted.

David Phillips (CSI): David Gregory Phillips is a fictional character on the CBS crime drama "", portrayed by David Berman, who also serves as head researcher for the series.  From Season 10 onwards David Berman has been credited in the opening titles.

Bugsy Siegel: Benjamin "Bugsy" Siegel (February 28, 1906 – June 20, 1947) was a Jewish American mobster.  Siegel was known as one of the most "infamous and feared gangsters of his day".  Described as handsome and charismatic, he became one of the first front-page celebrity gangsters.  He was also a driving force behind the development of the Las Vegas Strip.  Siegel was not only influential within the Jewish mob but, like his friend and fellow gangster Meyer Lansky, he also held significant influence within the Italian-American Mafia and the largely Italian-Jewish National Crime Syndicate.

Silver Jews: Silver Jews were an indie rock band from New York City, formed in 1989 by David Berman along with Pavement's Stephen Malkmus and Bob Nastanovich.  Berman remained throughout and was the only constant member.  During the last few albums, Cassie Berman became a regular member of the band.  They disbanded in 2009.

Easy Street (book): Easy Street: The True Story of a Mob Family (1981) is the first memoir of Susan Berman, daughter of Las Vegas mobster David Berman.  In it, Berman chronicles her mother Gladys's and her own obliviousness to what went on around them.  When they finally became aware of their Mafia family, Berman's mother ended up dying in a mental institution and Susan endured a lot of psychotherapy.

David Berman (mobster): David Berman (1903–1957), nicknamed "Davie the Jew", was a Jewish-American organized crime figure in Iowa, New York City, Minneapolis, and Las Vegas.  He was one of the pioneers of gambling in Las Vegas, where he was a partner with flamboyant mobster Bugsy Siegel at the Flamingo Hotel.  Berman died a non-violent death in 1957 during surgery.

Cohen crime family: The Cohen crime family, or the Siegel crime syndicate, was an Italian-American Mafia / Jewish Mafia crime family created by New York Jewish American mobster Benjamin "Bugsy" Siegel in the early 1930s.  Siegel ran Los Angeles and later Las Vegas' illegal gambling and prostitution rings with his lieutenants Mickey Cohen, David Berman, Harold "Hooky" Rothman, Moe Sedway and boss of the L.A. family Jack Dragna.

Bugsy (disambiguation): Bugsy is a 1991 film about the American gangster Bugsy Siegel.

Bugsy: Bugsy is a 1991 American crime-drama film directed by Barry Levinson which tells the story of mobster Bugsy Siegel and his relationship with Virginia Hill.  It stars Warren Beatty as Siegel and Annette Bening as Hill, as well as Harvey Keitel, Ben Kingsley, Elliott Gould, and Joe Mantegna.  The screenplay was written by James Toback from research material by Dean Jennings' 1967 book "We Only Kill Each Other".

Supporting paragraphs: David Berman (mobster) Bugsy Siegel
Answer: Jewish-American