ROGUE INFORMANTS IMPERIL MASSIVE U.S. GANG BUST

As a paid undercover informant, Jaime Martinez helped federal agents
take down the San Francisco chapter of Mara Salvatrucha, or MS-13, a
violent gang spanning the U.S. and Central America.

But while providing information to federal authorities from 2005 to
2008, Mr. Martinez also served as the gang's leader. He ordered
underlings to kill and steal, while he himself stole cars and led a
home robbery that ended with a stabbing, among other
transgressions.

Federal rules allow informants to engage in certain nonviolent
criminal acts-such as drug dealing-to maintain their covers as long as
they get prior authorization from agents. In testimony last month, Mr.
Martinez detailed a pattern of violent behavior that violated those
rules.

"I honestly didn't pay much attention" to those rules, Mr. Martinez
said in his May testimony as a government witness at a San Francisco
federal court trial of several MS-13 members.

The MS-13 probe is one of the federal government's biggest criminal
investigations and a centerpiece of its highly publicized assault on
street gangs, which Attorney General Eric Holder has called one of the
nation's "most overwhelming and intractable challenges." The Justice
Department has filed indictments and won convictions against scores of
alleged MS-13 members.

But the alleged misdeeds of Mr. Martinez and other MS-13 informants
could significantly damage that effort by tainting cases against gang
members, a review of the national MS-13 probe shows. Already,
questionable activities by MS-13 informants appear to have factored
into the acquittal of one alleged gang member as well as the Justice
Department's decision to drop death-penalty charges against at least
one other.

The government's handling of the MS-13 informants points to bigger
questions about how well government officials are controlling criminal
cooperators, who legal experts say are often vital to big-time
investigations.

"It's hard to break into any organized criminal group without an
informant," says Michael Rich, a professor at the Elon University
School of Law in North Carolina who studies informants.

Although the government won't disclose how many confidential
informants it has, the number has likely been rising post-9/11 as
federal investigators focus on domestic counterterrorism probes,
white-collar prosecutions and organized-crime cases including big
street gangs, Mr. Rich says.

Informants-usually criminals themselves-aren't an easy group to
manage. It's like playing "hardball with hand grenades," says Stephen
Trott, a federal judge and ex-prosecutor.

A 2005 Justice Department Inspector General's review of 120 Federal
Bureau of Investigation informants, the most recent such study
available, found over 85% of the cases contained violations of agency
guidelines, ranging from paperwork errors to unauthorized illegal
acts. In handling informants, there is "inadequate training at every
level," the report said.

The FBI said after the report that it was working to improve its
informant-control systems.

A February report from the Brennan Center for Justice at New York
University criticized the Justice Department for relaxing its
informant rules over the past decade. Among other things, the study
said, the department has let agents use more informants more
frequently by expanding the types of investigations in which
informants could be used and allowing them to take part much earlier
in a probe.

"Disrupting and dismantling violent gangs and criminal organizations
requires the use of all our investigatory and prosecutorial tools," a
Justice Department spokeswoman says, "including utilizing informants
with inside knowledge of these groups."

An FBI spokesman says the bureau uses a variety of mechanisms to
ensure the information collected from the informant is accurate and
obtained in compliance with regulations and the law.

Last year, the government attempted to deport a federal drug informant
who was caught smuggling drugs into the U.S. and was involved in at
least one murder in Mexico while working for the government. The
informant's government handler was fired.

In the MS-13 cases, federal agents sometimes didn't know about the
informants' questionable behavior, court records indicate. In other
instances, agents appear to have condoned it-once even providing money
for a gang leader to buy guns in El Salvador, a possible violation of
federal law.

In addition to Mr. Martinez, two other federal MS-13 informants, Jorge
Pineda and Roberto Acosta, were also high-ranking gang members who
have been implicated in violent crimes while providing information to
federal authorities.

Justice Department officials declined to answer questions about
Messrs. Martinez, Pineda and Acosta. An attorney for Mr. Martinez
declined comment. Mr. Pineda couldn't be located.

Salvadoran immigrants in Los Angeles formed MS-13 during the 1980s to
protect themselves from other gangs, say law-enforcement officials. By
the early 2000s, the gang had spread and become a top law-enforcement
concern.

Officials estimate there are 8,000 to 10,000 MS-13 members in about 30
states, and thousands more in Central America.

One early informant recruit was Mr. Pineda, a Salvadoran native who
moved to Los Angeles and became a MS-13 gang member and drug dealer
nicknamed "Dopey." Mr. Pineda said he offered his services to the FBI
in 2000 in an effort to adopt a "Christian life," according to his
testimony in a 2008 trial of other alleged MS-13 members.

Mr. Pineda testified he helped agents track gang activities and
identify high-ranking MS-13 leaders, known as "shot callers" and "big
homies,' nationally and overseas.

The Justice Department rules for informants allow certain nonviolent
infractions to maintain cover. But they prohibit informants from
committing violent crimes. Penalties can include forfeiture of the
agreement for leniency, criminal prosecution and deportation.

In his 2008 testimony, Mr. Pineda said that after agreeing to become
an informant in 2001, he stabbed a man outside a Los Angeles nightclub
that year and was given a prison sentence of about three years.

The FBI kept using him in prison, he testified, providing a cellphone
and arranging for him to secretly record conference calls with gang
leaders, including Nelson Comandari, identified in court documents and
interviews as a top MS-13 figure. Over a several-year period, he said,
he received $127,000 in government pay.

He once helped Mr. Comandari avoid arrest by lying to the FBI about
the top gang leader's whereabouts, Mr. Pineda acknowledged in his
testimony. He said he feared other gang members would know he was an
informant if Mr. Comandari was apprehended.

Last year, New York federal prosecutors dropped capital-murder charges
against an alleged MS-13 member after his attorneys argued misdeeds by
Mr. Pineda had tainted the case. In a recording made by another
informant, Mr. Pineda gave guidance to gang members on when to commit
murders, according to one of the defendant's lawyers, Russell Neufeld.
The alleged gang member pleaded guilty to causing a death with a
firearm and is now serving a 35-year prison sentence.

A Justice Department spokesman in New York declined to
comment.

While he was on the government payroll, Mr. Pineda asked San Francisco
MS-13 members in a 2004 phone call about their plans to retaliate for
the murder of their leader by a rival. He asked if they "are going to
commit a massacre," adding that "now is the time," according to an FBI
report reviewed by The Wall Street Journal. He ordered Los Angeles
gang members to bring weapons, including an M14 machine gun, to San
Francisco, the report said.

The San Francisco gang, known as the 20th St. clique, "became more
bloodthirsty beginning in 2004 and 2005," with the arrival of MS-13
gang members from Los Angeles and elsewhere, according to a court
filing in the San Francisco case.

One arrival was Roberto Acosta, a Honduran native who in early 2005
became an informant for Immigration and Customs Enforcement, or ICE,
another major federal agency in the MS-13 investigation.

Mr. Acosta recorded conversations with San Francisco gang leaders and
gave younger gang members MS-13 tattoos-which prosecutors later used
as evidence of gang membership, according to court documents and testimony.

While an informant, Mr. Acosta sold crack cocaine and encouraged gang
members to extort and beat other drug dealers, according to taped
transcripts and testimony by Mr. Martinez, who said he witnessed some
of the acts.

ICE deported Mr. Acosta to Honduras in 2006 for cutting off contact
with his handler, according to people briefed on the matter.

By then, federal agents had turned to Mr. Martinez, a Salvadoran
native who came to San Francisco as a teen and had become leader of
the city's MS-13 gang. Mr. Martinez was arrested on a firearms charge
around 2005, he has testified, and cut an informant deal with ICE "to
save my own skin."

In 2006, while an informant, Mr. Martinez and three other gang
members, including one nicknamed "Psycho," robbed a grocery-store
worker in San Francisco. In the May testimony, Mr. Martinez said he
held the victim against a wall while Psycho took the man's house keys.
The robbers went to the house, where Mr. Martinez said he watched the
others stab a man who lived there. No one was arrested, he said.

Mr. Martinez persuaded ICE agents to give him $200 in March 2007 to
send to a high-ranking MS-13 member in El Salvador to buy guns, he
testified. ICE gave him a similar amount of money to send to El
Salvador later that year, Mr. Martinez testified. Some of the money
went to buy a cellphone, the government said.

That October, Mr. Martinez was arrested with a stolen car. He
testified that he called his ICE agent to complain about being held
for possible deportation.

ICE reviewed Mr. Martinez's informant status, reminded him he wasn't
allowed to commit crimes and then released him from custody, the agent
testified in a San Francisco federal trial last year. ICE continued
using him as an informant-though in 2008 he spent more than six months
in a county jail for the auto theft.

In a statement, ICE said it takes "significant steps" to oversee
informants, including the training of ICE agents and the auditing of
case files.

Several days after his October 2007 arrest, Mr. Martinez testified, he
was riding in San Francisco with a relative in a stolen van when they
spotted a party that seemed to include members of a rival gang. Mr.
Martinez said he and his relative got a shotgun and two other gang
members and returned to the party.

"I listened for them to do the shooting. When they came back I just
took off driving," Mr. Martinez said. No arrests were made.

"He was an informant for the government when he was driving the
getaway car?" Judge William Alsup, who is presiding over the MS-13
trial in San Francisco, asked in court.

"Yes," said Wilson Leung, the assistant U.S. attorney.

"It doesn't look good when the government's people are out there
helping commit crimes, maybe even murders," the judge replied.

On Oct. 25, 2007, ICE agents signed a new agreement with Mr. Martinez,
apparently unaware of the shotgun incident.

The agreement provided him with a $2,000 monthly salary, replacing a
previous agreement that paid him $300 to $600 per tip. All told, Mr.
Martinez has received more than $100,000 from the government,
according to a person briefed on the matter.

A San Francisco federal grand jury indicted 31 alleged MS-13 members
in October 2008. About half the defendants have pleaded guilty.

The only San Francisco defendant to get a jury verdict was acquitted
on car theft and conspiracy charges last year after Mr. Martinez, the
government's key witness, testified that he helped orchestrate the car
thefts while an informant.

Mr. Leung, the assistant U.S. attorney on the case, has acknowledged
in court hearings that Mr. Martinez broke federal informant rules. He
explained in another MS-13 trial last year that while Mr. Martinez
"reminded his fellow gang members of the need to go attack" rivals and
snitches, he "did not authorize any particular hits that resulted in
any particular violence."

Mr. Leung and other federal officials declined to answer questions
about Mr. Martinez, who is now in a federal witness-protection
program, prosecutors said in recent hearings. He has pleaded guilty to
an MS-13 conspiracy charge and recently testified he expected leniency
for his cooperation.

Around 2008, meanwhile, Mr. Acosta illegally re-entered the U.S.,
court records and testimony show, and federal officials allowed him to
resume his informant work, spending over $175,000 relocating him and
10 family members.

Last February, as prosecutors prepared to try seven alleged San
Francisco MS-13 members on conspiracy charges, Mr. Acosta, a potential
star witness, allegedly made a shocking admission in a private meeting
with prosecutors, according to court records. While in Honduras, he
had murdered at least eight people, including some on a public bus,
according to those records and people briefed on the matter.

The government indicted Mr. Acosta for lying about his Honduran
activities when he re-entered the informant program. A lawyer for Mr.
Acosta, Elena Condes, declined to comment on whether her client has
admitted to killing people. But she said Mr. Acosta disputes
prosecutors' accusation that he lied about his criminal past, and said
he plans to stand trial next month on the charge of making false
statements to investigators.

Mr. Pineda's whereabouts are unknown. No criminal charges are known to
be pending against him.