I am aware of Arvanites and they have been here for thousands of years, I'm not debating racial purity or anything, i'm saying the last wave was disproportionately responsible for crime in Greece. Here are two sections from the Wikipedia entry on crime in Greece.

Organized crime[edit]
See also: Greek mafia
Organized crime in Greece is on the rise.[3] Domestic as well as foreign criminal groups are well-entrenched in Greek society. Traditionally, people associated with organized crime were known as Men of the night (άνθρωποι της νύχτας). Out of the foreign criminal groups the Albanian mafia is the most prevalent. The activities of the Albanian crime groups in Greece include drug trafficking, human trafficking, extortion and robbery among others.

Albanian criminal groups often extort other immigrants to Greece, especially Middle Eastern and Pakistani shopkeepers, and control many nightclubs in the working-class districts of West Athens. Russian groups are less numerous, but they are very heavily armed and dangerous; they are involved in arms trafficking, extortion and cigarette smuggling. Lower-level Romanian and Moldavian groups are involved in theft and human trafficking.[4]

Immigrant crime[edit]
Further information: Immigration to Greece
Official statistics show that immigrants are responsible for about half of the criminal activity in Greece.[6] The Greek police have admitted that armed gangs entering the country from neighbouring Albania or Bulgaria could have been attracted by reports that many people have been withdrawing cash from banks and stashing it in their homes.[6] There are possibly more than 1 million illegal immigrants inside Greece as of 2012.[6][7] Cases of immigrant crime such as the 2012 Paros rape have attracted nationwide interest.

Illegal immigration to Greece has increased rapidly over the past several years. Tough immigration policies in Spain and Italy and agreements with their neighboring African countries to combat illegal immigration have changed the direction of African immigration flows toward Greece. At the same time, flows from Asia and the Middle East — mainly Pakistan, Afghanistan, Iraq, and Bangladesh — to Greece appear to have increased as well.[7]
包含语种1:English，语种2:Greek