At 2 a.m. on a hot summer night a series of shots ring out on a residential street. The body of an 18-year-old Latin Kings gang member falls to the ground and a car speeds off.

You arrive to see a dead body lying on the sidewalk and are met by two other Latin Kings members who were sharing a marijuana cigarette and beers with the victim at the time of the shooting. The two gang members report that they narrowly missed getting hit. They saw a man with a mask on his face fire a gun and kill their friend.

Another Latin King across the street on the porch with his girlfriend saw a man exit the passenger seat of a car, put on a mask, and fire a gun. He saw the offender's face. He also was able to get the make, model, and a partial license plate of the car. Porch Gangsta identifies the offender as a Two-Six Boy gang member, rivals of the Latin Kings.

Two days later, a Two-Six boy is arrested on a traffic stop for narcotics possession. He is on probation. The arrestee tells your fellow officers about a fellow Two-Six gang member who confided in him that he had killed a Latin King. He leads investigators to the hiding spot of the murderer.

Because of their involvement with criminal activity and those involved in illegal enterprise, gang members are likely to be witnesses to criminal acts. In a murder of a gang member, for example, very often the only witnesses will be gang members themselves.

Further, gang members get in trouble and get arrested. They also become embroiled in inter- and intragang rivalry. So gang members may reach out to you to share information about what they may have witnessed or heard.

That means that you need to be aware of issues that will come up in gang cases as well as the steps to take so that your case can lead not only to an arrest but to a successful prosecution of dangerous criminals.

Initially Cooperative

Gang members, along with friends and family of the offender, may not be cooperative. They may try to be inaccessible to you after the offender is arrested. They may even go into hiding. Make every effort to locate every possible witness to the case because you're going to need them.

In helping to prepare a case for trial, always be aware of the possibility, or the likelihood, that when the friends, family, and fellow gang members of the offender come to court for the trial they may be less than truthful in their testimony about the incident in question.

Gang members will often seem to be cooperative initially in speaking with police shortly after the commission of a crime, but they will often "flip," or change their version of events with the passage of time. After the incident, when they return to their neighborhoods and interact with their friends, they will often feel intimidated or threatened, or they will feel shame or stigma for cooperating with police. Of course, this is not always the case, but prepare for the possibility.

Witness Protection

Wise investigators make an effort to provide for the safety of witnesses, especially witnesses who have information on gang crimes. And that includes gang members.

So before trial, inquire as to whether there have been any attempts made to intimidate witnesses. If requested, protection should be offered and arrangements should be made. But don't make promises that you cannot or will not keep.

Investigators and gang members will likely be in contact with each other in the future due to the nature of their respective roles in society. It will always serve you well to be known as a person who keeps your word.

Gather Intel

It is important to establish a rapport with gang members and to maintain intelligence on them.

Rival and same-gang members, along with gang girlfriends and wives, are a great source of gang intelligence. Learn about gang tattoos, gang symbols, colors, territory, rivalries, allegiances, gang factions, slogans, and boundaries. Always document these in reports. And keep separate files for your own background.

True or False

When speaking with a gang member who has witnessed a crime, consider his motives to tell the truth. Consider his motives to lie.

Be very careful to separate witnesses. Let the witnesses tell you what has happened. Do not put words in the gang member witnesses' mouths. And don't feed them answers.

Ideally, if there are neutral, non-involved, and seemingly non-biased witnesses, use them as lie detectors for the gang witnesses. Get the neutral witnesses' version of events first, if possible, so that you have an idea of what happened before speaking with the gang member. This makes it easier to corroborate or refute what the gang member tells you.

With a gang member witness, if you believe that he is telling the truth, but feel he may change his story at some point, consider documenting what he has told you in a handwritten statement.

Also, anticipate that there may be future claims of mistreatment by the police and document the way that the witness was treated. Document the lack of coercion, threats, and promises. Document if the witness was allowed to eat, drink, smoke, use the bathroom, and sleep in the police station. Obtain a signed statement, including a section that covers treatment.

Witnesses can also be brought before the grand jury, and placed under oath. The grand jury is a great tool for an investigation in that it locks witnesses into sworn testimony regarding what that person heard or witnessed.

Exert Some Pressure

Many gang members may be reluctant or unwilling to get involved in a case as a witness when a fellow gang member has committed a crime. Ultimately, if it can be shown that someone has knowledge of a crime, police have some leverage over that person.

If a witness saw a crime, he or she cannot opt out of the investigation. Fifth Amendment rights only apply to an individual's rights not to incriminate his- or herself. So a person does not have a specific right not to incriminate fellow gang members.

Many, if not most gang members, will willingly come down to the station to talk to police if they are only witnesses. This, of course, does not mean that they will be truthful. This is where you can exert pressure to get the truth.

The government has the right to subpoena witnesses. If witnesses refuse to comply with the justice process, they may be subject to penalties for contempt of court and obstruction of justice. If they come to court and lie, they can be charged with perjury.

In a perfect world, all witnesses to crimes would be law-abiding, sober persons, who could not be impeached in court. They would be people motivated by the greater good to do the right thing.

That may happen in Shangri-La, but it never happens in gang cases. Frequently these witnesses may be members of the same or a rival criminal organization with a variety of motivations for being witnesses, including giving notice to another gang that they will defend their territory and fingering a rival gang member.

In cases involving gang violence, get to the scene quickly, find the witnesses, and document who these witnesses are and what they say. Then if gang members do change their version of events, at least it can be explained why this person did what he or she did.

Such a strategy ensures a greater likelihood of the truth coming out in the investigation and later at the trial. It also gives you a chance to make the streets of your community safer by sending dangerous criminals to the penitentiary.

Patrick Morley is an Assistant States Attorney in Cook County, Ill., and a prosecutor assigned to the Cold Case Unit.The former Chicago police officer is also a law enforcement training instructor.