Probably held a job just long enough to qualify for Social Security and/or SSDI and then cashed in.
Police departments hiring immigrants as officers
Alan Gomez, USA TODAY 2:56 p.m. EDT March 21, 2015
Law enforcement agencies struggling to fill their ranks or connect with their increasingly diverse populations are turning to immigrants to fill the gap.
Most agencies in the country require officers or deputies to be U.S. citizens, but some are allowing immigrants who are legally in the country to wear the badge. From Hawaii to Vermont, agencies are allowing green-card holders and legal immigrants with work permits to join their ranks.
http://www.usatoday.com/story/news/nation/2015/03/21/immigrant-police-officers/70236828/