The defendants are accused of murdering or trying to murder 25 people in a quest for control of Southern California drug gangs.
The charges include murder, racketeering, attempted murder, drug sales, conspiracy and extortion, reported The Associated Press.
The government used undercover surveillance tape (pictured) to try to prove their case, said CBS 2 News.
The defendants have claimed that the Mexican Mafia doesn't exist and that the government's key witness, Ernest "Chuco" Castro, gave unreliable evidence to save himself from prosecution, said AP.
Yesterday, the last defense lawyer in the trial ended his closing argument by serenading jurors with a Sinatra tune.
Attorney Bernard Rosen first quoted, then sang a few lines of "Where or When?" as he argued that the government did not come up with enough evidence against his client, alleged Mexican Mafia co-founder Benjamin "Topo" Peters.
Rosen also claimed that the government has failed to prove racketeering and conspiracy charges, and was using "any means necessary" to prosecute Peters by adding a charge against him to which he had already pleaded guilty in state court.
This is the first time gang members have ever been prosecuted under federal racketeering laws, according to CBS 2 News.
Compiled by C.C. SandorfiChannel 2000 Staff Writer, from CBS 2 News, Associated Press reports
Mexican Mafia Case Goes to Trial
LOS ANGELES, Posted 7:45 p.m. May 16, 1997 -- A Los Angeles jury has begun deliberating the fate of 13 alleged members of the Mexican Mafia.