Got a call from this number and when i refuse to give info they started speaking another lanuage

Caller from this number called my work and my cell phone and left a threatening message.  He identified himself as officer normal gilbert and said that they are about to download a lawsuit against me to the united states and will not be responsible for the result.  They had the last four digits of my social security number!  Heavy indian accent.  Who is this? and what is it all about?  Is this a scam?

Ignore the calls.......if they are from any of the following numbers:  
Neil McZennzey 2062121102
Dave Mathew 6462132852
Daveid Logan 6613476528
David logo 6613476528
Neil Stevens 707.797.7261

called earlier today from number "052639886" on my caller id.  Said his name was Roy Freeman with the Federal Crime Investigation.  Haha..  What a scam.. Anyone have any more information on these people?

Got a call from "Officer Roy Freeman" with the Federal Crime Investigations this morning.  States I have 2 choices, to pay him right now or to go to court.  And he has all the evidence against me.  States I took out a loan from US Fast Cash International and have failed to pay it back.  "The money was put into your bank account." he stated.  He was unable to give me any details regarding this supposed transfer of money.  I then asked him for the phone # for the loan company so I can settle with them because I had not gotten any such loan.  He then states that I would need to speak to him, he is with US Fast Cash International (Even though he said initially he was with Federal Crime Investigations.)  He did spout off the last 4 of my ssn and also some other info about me.  THe call came through at work and was a blocked number.  There was also a message on my cell phone from a +052639886 number....How do you get these people to stop?