GLAD YOU'RE SHARING WITH US TODAY. WELL, MEXICAN POLICE HAVE ISSUED AN ARREST WARRANT IN THE DEATH OF THAT AMERICAN TOURIST, SEAN ROBINSON. INVESTIGATORS SAY THEY BELIEVE THE TWENTY FIVE YEAR OLD WAS KILLED BY AN ACQUAINTANCE. >> AND NOW THERE ARE NEW QUESTIONS ABOUT HOW JUSTICE WILL WORK ACROSS THE BORDER HERE. MATT RIVERS HAS MORE FROM MEXICO CITY. >> MEXICAN AUTHORITIES SAY THEY BELIEVE 25 YEAR OLD U.S. CITIZENS TRANQUILLO ROBINSON WAS KILLED BY AN ACQUAINTANCE. ANOTHER AMERICAN WOMAN, WHILE ON VACATION IN LOS CABOS. ROBINSON WAS FOUND DEAD AT A LUXURY RESORT IN LATE OCTOBER, TRAVELING WITH A GROUP OF FRIENDS WHOSE ACTIONS IMMEDIATELY BECAME SUSPICIOUS AND ONE NOW VIRAL VIDEO TOO VIOLENT TO SHOW. ROBINSON IS SEEN BEING SEVERELY BEATEN BY ANOTHER WOMAN IN HER HOTEL ROOM, WHILE AT LEAST TWO PEOPLE IN THE ROOM WATCH OR RECORD THE INCIDENT. IN ANOTHER, SOMEONE FILMS ROBINSON TAKING A NAP THE DAY BEFORE SHE WAS KILLED BY A POLICE REPORT FROM THE DAY SHE DIED, SAYS GUESTS AT THE RESORT CALLED FOR MEDICAL HELP, CLAIMING SHE HAD DRUNK A LOT OF ALCOHOL. A DOCTOR SAID SHE WAS, QUOTE, STABLE BUT DEHYDRATED, ADDING THAT THE GUESTS REFUSED TO BRING HER TO A HOSPITAL. THE POLICE REPORT SAID SHE WENT INTO CARDIAC ARREST AND WAS DECLARED DEAD AT SIX P.M.. BUT AN AUTOPSY OBTAINED BY ABC NEWS CONTRADICTED THAT REPORT, SAYING SHE WAS DECLARED DEAD THREE HOURS EARLIER, SUFFERING FROM A SEVERE SPINAL CORD INJURY AND A DISLOCATED NECK. >> THEY ATTACKED AND IT WAS NOTHING SHE COULD DO. AND NOW SHE WOULD STAY IS NO. >> SHE WENT BOTHER. NO WAY. SHE HAD A GOOD HEART. MEXICAN AUTHORITIES NOW SAYING THE PRIME SUSPECT IN THE CASE BACK IN THE UNITED STATES , THE FACT THAT THE PERSON ACCUSED IS AN AMERICAN CITIZEN FUNDAMENTALLY CHANGED ALL OF THE EVALUATION HERE. >> MEXICAN PROSECUTORS FILING CHARGES FOR FEMICIDE, WHICH MEANS THEY BELIEVE ROBINSON WAS KILLED, AT LEAST IN PART BECAUSE OF HER GENDER . MEXICO IS ASKING THE U.S. TO EXTRADITE THE SUSPECT TO FACE CHARGES IN MEXICO. >> THE DEPARTMENT OF JUSTICE WILL HAVE TO EVALUATE ANY EVIDENCE IF THE U.S. AUTHORITIES AND POTENTIALLY A U.S. COURT ARE NOT CONVINCED THAT THE MEXICANS HAVE A VERY STRONG CASE, THAT IT'S VERY UNLIKELY THAT SHE WOULD BE EXTRADITED. >> NOW, U.S. AUTHORITIES COULD ALSO CHOOSE TO PROSECUTE THIS CASE THEMSELVES. AND WE KNOW THE FBI IS ALREADY INVESTIGATING. BUT I SPOKE TO ONE FORMER US DIPLOMAT BASED HERE IN MEXICO WHO TELLS ME THAT IT'S ALL ABOUT WHETHER THE MEXICAN GOVERNMENT WILL COOPERATE HERE . WILL THEY TURN OVER THEIR CASE FILES? WILL THEY ALLOW THE FBI THE ACCESS THEY NEED TO PROPERLY INVESTIGATE THOSE REMAIN OPEN QUESTIONS AT THIS POINT KYRA. ALL RIGHT, MATT RIVERS, THANKS SO MUCH. AND SO FOR MORE ON THIS INTRIGUING CASE, LET'S BRING IN FORMER NYPD CHIEF OF DETECTIVES AND ABC NEWS CONTRIBUTOR ROBERT BOYCE. AS WAS ABC NEWS CONTRIBUTOR, MANAGING PARTNER AT THE COCHRAN LAW FIRM, CHANNA LLOYD. SO, SEAN, LET ME BEGIN WITH YOU ON THIS QUESTION OF EXTRADITION. IF, IN FACT, A SUSPECT IS DEVELOPED. THE BIG QUESTION NOW IS HOW WOULD THAT PROCESS WORK FROM THE U.S. TO MEXICO? HOW MUCH WE SEE THE MOVIES PEOPLE RUN ACROSS THE BORDER, BUT HOW EFFECTIVE IS THE EXTRADITION PROCESS IN ACHIEVING JUSTICE? FOR A SUSPECT WHO'S IN MEXICO? >> WELL, IT'S INTERESTING BECAUSE WE DO HAVE A TREATY THAT SAYS THAT THERE CAN BE EXTRADITION WHEN PERSONS ARE FOUND TO HAVE COMMITTED A CRIME. NOW, THIS ONE'S INTERESTING BECAUSE WE HAVE THE ACTUAL U.S. CITIZEN WHO'S ACCUSED OF THE CRIME, WHO IS STILL IN THE U.S. . MEXICO ACTUALLY HAS TO SUBMIT OR REQUEST TO HAVE THIS INDIVIDUAL ARRESTED AND THEN EXTRADITED. >> IT IS A VALUE CREATED BY THE STATE DEPARTMENT AND THE DEPARTMENT OF JUSTICE, CRIMINAL INVESTIGATIONS, INTERNATIONAL AFFAIRS OFFICE. ONCE THEY HAVE FOUND THAT THE LEGAL FINDINGS ARE SUFFICIENT TO RISE TO THE LEVEL OF CRIMINALITY, IT'S THEN FORWARDED TO A DISTRICT JUDGE TO ISSUE THAT ARREST WARRANT AND THEN A HEARING AT THAT HEARING. ALL THE EVIDENCE IS PRODUCED FROM WHAT THE MEXICO AUTHORITIES HAVE GATHERED. AND THERE'S A DETERMINATION IF THERE'S ENOUGH LEGALLY SUFFICIENT INFORMATION IN THIS INVESTIGATION. TO DETERMINE CHARGES THAT WOULD SUPPORT EXTRADITION. SO COULD WE SEE MEXICO ENGAGE IN THE PROSECUTION? >> AND REGARDLESS OF WHAT THE SUSPECT IS EXTRADITED OR NOT, ABSOLUTELY, BECAUSE THE U.S. CAN ACTUALLY SEEK TO BRING CHARGES AGAINST THIS SUSPECT'S CURRENT. MEXICO HAS TO SUPPORT THE INVESTIGATION BY PROVIDING ALL OF THE INFORMATION, THE EVIDENCE AND ALL OF THEIR CASE FILES THAT THEY CURRENTLY HAVE, BECAUSE THAT'S WHAT THE U.S. WOULD BE MAKING ANY DETERMINATION BASED ON . >> AND BOB, THIS INVESTIGATION ACROSS AN INTERNATIONAL BORDER IS GOING TO BE COMPLICATED. HOW MUCH COOPERATION WOULD THE UNITED STATES GET FROM FROM AUTHORITIES, POLICE, INVESTIGATORS IN MEXICO? DOES THAT WORK SMOOTHLY? MOST OF THE TIME? >> IT DOES, BUT IT DEPENDS ON THE ISSUE AND THE ISSUE HERE IS YOU HAVE A BIG, BIG PROBLEM AND THE TIMELINES ARE GOING FORWARD. YOU HAVE MEDICAL REPORTS, WHICH IS THEY CALL IT 215 OR THEY LEAVE AND THEN THEY COME BACK AND THEN SHE'S DECLARED DEAD AT SIX CLOCK. THAT'S NOT INDICATED ON THE CORONER'S REPORT. THIS A BIG PROBLEM IS THAT IT WAS TRUE BEFORE ANYTHING. THIS GOES FORWARD. ALSO, WE DON'T KNOW WHAT HAPPENED BEFORE THAT TERRIBLE VIDEO THAT WAS SHOT OR AFTERWARDS OR WHAT TIME THAT WAS. THERE'S SO MANY QUESTIONS HERE. IT'S GOING TO TAKE A WHILE TO HASH OUT WHAT I THINK IT WILL GET DONE. IN THE END. IT'S JUST WHIT JOHNSON BEFORE. IF NOT, THE FBI WILL PROSECUTE THOSE PERSONS HERE IN THE U.S. IF THEY CAN'T GET ANY THAT THEY NEED. >> SO THEN, BOB , THE MEXICAN INVESTIGATORS DROPPED THE BALL HERE IN THE INITIAL STAGES OF THE INVESTIGATION. >> I CAN'T SAY THAT WITHOUT THAT INFORMATION, BUT I'LL TELL YOU ONE THING. IT DOES SEEM TO BE COORDINATED. WHAT WHAT THE REPORTS ARE COMING OUT OF THERE THAT THE PROSECUTOR, MR. MANDELA, SAID. NOW, I SAID BASICALLY THEY HAVE A CLARIFY CASE. I DON'T SEE HOW THAT'S POSSIBLE WITH THESE CHANGES. CLEARLY, THIS THINGS HAVE CHANGED TWO WEEKS AFTER THE EVENT WITH THE VIDEO GOING VIRAL LIKE THAT, WHICH CHANGED EVERYTHING. AND NOW WE HAVE THE MEXICAN AUTHORITIES WITH AN ARREST WARRANT FOR U.S. CITIZEN. SO THINGS ARE REALLY RATCHETING UP HERE. I THINK IT'S REALLY A LONG TIME BEFORE THAT FILLED WITH ROB MARCIANO. WE HAVE THE ANSWERS THEY WANT. I THINK IT'S GOING TO HAPPEN TO JUST TAKE A WHILE. >> YEAH, THAT THAT'S THE POINT OF IT DOES LOOK LIKE NOW THAT THERE'S SO MUCH ATTENTION, THERE'S ALL THIS MAKES IT MORE DIFFICULT. AND I WONDER ABOUT THE ROBINSON FAMILY. SHONNA, WHAT WHAT RECOURSE DOES THE FAMILY THIS THIS YOUNG WOMAN, YOU CUT DOWN KILLED IN IN THE PRIME OF HER LIFE, WHAT RECOURSE DID THEY HAVE WHILE THESE WHEELS OF JUSTICE IN TWO DIFFERENT COUNTRIES GRIND AWAY ? UNFORTUNATELY, THEY DON'T HAVE A LOT OF INFLUENCE ON THE SYSTEM. VICTIMS ARE TYPICALLY AND THEIR FAMILIES ARE ASSIGNED A VICTIM ADVOCATE TO WALK THEM THROUGH THE PROCESS. BUT THIS PROCESS IS STRICTLY BETWEEN OUR STATE DEPARTMENT, THE FBI, AND THE MEXICAN GOVERNMENT RIGHT NOW. SO YOU DON'T HAVE AS MUCH INFLUENCE TO PUSH NOW. THEY CAN ALWAYS WANT TO ENCOURAGE THEM TO KEEP INVESTIGATING IF THEY DON'T HAVE ANY AUTHORITY RIGHT NOW FOR THE FAMILY. >> YEAH, IT'S SUCH A DISTURBING CASE IN SO MAN